I need help with 6 and 7

Answer:

765,000 Joule

Explanation:

Principle of Conservation of Energy

The total energy in an isolated system cannot be created or destroyed, but transformed. Moving objects have kinetic energy, objects placed in some height above a reference level have gravitational potential energy. When they change their motion variables, one energy converts into the other, but if the numbers don't fit, we know there was some other type of energy acting into the system. The most common reason for energy 'losses' is the thermal energy, produced when objects move in rough surfaces or take friction from the air.

The 7,500 kg truck is originally traveling at 20 m/s to a certain height we'll set to 0. Thus, its total energy is  

[tex]\displaystyle E_1=\frac{mv^2}{2}[/tex]

[tex]\displaystyle E_1=\frac{7,500\ 20^2}{2}[/tex]

[tex]E_1=1,500,000\ Joule[/tex]

When it comes to a stop, its speed is 0 and its height is 10 m higher than before. It means all the kinetic energy was transformed into other types of energy. The gravitational potential energy is

[tex]U=mgh=(7,500)(9.8)(10)=735,000\ Joule[/tex]

Since this number is not equal to the previous value of the energy, the difference is due to thermal energy dissipated by friction

[tex]E_t=1,500,000\ Joule-735,000\ Joule=765,000\ Joule[/tex]

The change in momentum is equal to 1.3928 kg.m/s².

The kinetic energy of the ball as it strikes the surface = 2.94 Joules

Given:

Mass of the ball = 100 g = 100 × 10⁻³ kg = m = 0.1 kg

Height from which ball falls = h = 3 m

Height to which the ball rebounds = h' = 2 m

g= acceleration due to gravity = g = 9.8 m/s²

1. A ball dropped from a height of 3 m, hits the horizontal surface and bounces back. This will cause a change in momentum.

The velocity of the ball before hitting the surface and after hitting the surface is different; causing a change in momentum (Δp).

Since momentum (p) = mass (m) × velocity (v) : [tex]p=m\times v[/tex]

Δp = [tex]m\times V_\ after[/tex] [tex]-\ m\times V_\ before[/tex] = [tex]m\times (V_\ after[/tex] [tex]\ -\ V_\ before[/tex] [tex])[/tex] ...........................(1)

Velocity (v) is given by [tex]v = \sqrt{2gh}[/tex]

[tex]V_\ before[/tex] = [tex]\sqrt{2\times g\times h} = \sqrt{2\times 9.8\times 3} = \sqrt{58.8} = 7.668\ m/s^2[/tex]

[tex]V_\ after[/tex] = [tex]\sqrt{2\times g\times h'} = \sqrt{2\times 9.8\times 2} = \sqrt{39.2} = 6.2609\ m/s^2[/tex]

[tex]V_\ before[/tex] is a decreasing quantity (Ball dropped from 3 m) until it becomes equal to [tex]V_\ after[/tex] and hence is a negative vector (negative in sign and opposite in direction to [tex]V_\ after[/tex].)

[tex]V_\ before[/tex] = (-7.668 m/s²)

From (1), for m = 0.1 kg, Δp becomes;

Δp = [tex]m\times (V_\ after[/tex][tex]\ -\ V_\ before[/tex][tex])[/tex] =  [tex]0.1( 6.2609 - ( - 7.668)) = 0.1\times 13.9289 = 1.3928\ kg.m/s[/tex]

2. As a ball falls to the surface, its gravitational potential energy is transformed into kinetic energy. This kinetic energy keeps on increasing with increase in momentum until it strikes the surface.

K.E of ball just before it strikes the surface from 3 m height = [tex]K.E = mgh[/tex]

[tex]K.E = 0.1\times 9.8\times 3 = 2.94\ J[/tex]

Answer:

B: it is the instantaneous speed of the bike rider.

Explanation:

keep it going....

Answer:

B It is the instantaneous speed of the bike rider.

Explanation:

I took  the test

Answer:

The primary reason that power is transmitted at high voltages is to increase efficiency. As electricity is transmitted over long distances, there are inherent energy losses along the way. ... The higher the voltage, the lower the current. The lower the current, the lower the resistance losses in the conductors.

Explanation:

Answer:

24 m

Explanation:

initial velocity is u = 3.5 m/sec

final velocity is v = 0 m/sec

distance traveled is S = 1.5 m

From kinematic equation [tex]v^{2}-u^{2} = 2as[/tex]

Making acceleration the subject,

[tex]a=\frac {v^{2}-u^{2}}{2s}[/tex]

Acceleration [tex]a = \frac {0^2-3.5^2}{(2*1.5)}= -4.083333333m/s^{2}[/tex]

When the initial velocity is quadrupled= u = 3.5*4 = 14 m/s

V = 0 m/s

[tex]a = -4.083333333m/s^{2}[/tex]

then [tex]S = \frac {v^{2}-u^{2}}{2} = \frac {0^{2}-14^{2}}{2\times -4.083333333} = 24 m[/tex]

The gain in gravitational potential energy of the mass = 100 kg m^2 / s^2.

Explanation:

Gravitational potential energy is an energy in which an object possesses because of its position in a gravitational field. The most common use of gravitational potential energy is for an object near the Earth's surface where the gravitational acceleration can be assumed to be constant at about 9.8 m/s2.

The formula for the gravitational potential energy is the product of mass, gravity, and height.

             GPE = m *g *h

where m represents mass in kg,

           g represents the gravity,

           h represents the height.

          GPE    = 5 * 10 * 2 = 100 kg m^2 / s^2.

Answers:

a)The balloon is 68 m away of the radar station

b) The direction of the balloon is towards the radar station

Explanation:

We can solve this problem with the Doppler shift equation:

[tex]f'=\frac{V+V_{o}}{V-V_{s}} f[/tex]  (1)

Where:

[tex]f=250,000 Hz[/tex] is the actual frequency of the sound wave

[tex]f'=240,000 Hz[/tex] is the "observed" frequency

[tex]V=340 m/s[/tex] is the velocity of sound

[tex]V_{o}=0 m/s[/tex] is the velocity of the observer, which is stationary

[tex]V_{s}[/tex] is the velocity of the source, which is the balloon

Isolating [tex]V_{s}[/tex]:

[tex]V_{s}=\frac{V(f'-f)}{f'}[/tex]  (2)

[tex]V_{s}=\frac{340 m/s(240,000 Hz-250,000 Hz)}{240,000 Hz}[/tex]  (3)

[tex]V_{s}=-14.16 m/s[/tex] (4) This is the velocity of the balloon, note the negative sign indicates the direction of motion of the balloon: It is moving towards the radar station.

Now that we have the velocity of the balloon (hence its speed, the positive value) and the time ([tex]t=4.8 s[/tex]) given as data, we can find the distance:

[tex]d=V_{s}t[/tex] (5)

[tex]d=(14.16 m/s)(4.8 s)[/tex] (6)

Finally:

[tex]d=68 m[/tex] (8) This is the distance of the balloon from the radar station

Answer:

It will have a certain kinetic energy at the beginning, but it will be lost by resistant work done by friction. Thus, itsmotion wil be uniformly decelerating.

Explanation:

Answer:

variable that scientist change

Explanation:

Answer:

Two objects are identical except that on is hotter than the other. Thus, when an equal force acts on them the hotter one will move faster or will get displaced more or stop slower than the other one. This is because the hotter object has comparatively more mobile particles than the other

Hope this helps!

Final answer:

Identical forces exerted on two objects with different temperatures will affect them equally according to Newton's third law, but their responses, such as stress and expansion, may differ due to properties like thermal expansion coefficients. Also, at thermal equilibrium, the final temperature is closer to the object with greater heat capacity. The hotter star of two identical stars will be significantly brighter.

Explanation:

Response to the Student's Question

When two objects are identical except for temperature and they are exposed to identical forces, the forces they experience will be the same due to Newton's third law. However, the effect of the force may differ if their temperatures lead to different physical properties like thermal expansion. If object A has a higher thermal expansion coefficient than object B and both are heated identically, A will likely feel greater stress because it will expand more, which could create internal strain if constrained. For the question about the heat capacities, when two objects—one hot, one cold—are brought into contact, the final temperature at thermal equilibrium will be closer to the object with the higher heat capacity, in this case, the colder object. Therefore, it will not be exactly halfway between the two initial temperatures.

In the context of stars, brightness is related to temperature. The star with a temperature of 8700 K will be brighter than the star at 2900 K due to Wien's Law and the Stefan-Boltzmann Law, which relate temperature to luminosity and energy output. The hotter star is, therefore, significantly brighter.

Answer:

The characteristics of water waves is that it travels through the waver, the particles travel in clockwise circles. The radius of the circles decreases as the depth into the water increases.

Explanation:

Answer:

ΔU = -70 J

Explanation:

ΔU = Q − W

where ΔU is the change in internal energy,

Q is the heat absorbed by the system,

and W is the work done by the system (on the surroundings).

30 J of thermal energy is released, so Q = -30 J.

40 J of work is done by the system, so W = 40 J.

Therefore, the change in internal energy is:

ΔU = -30 J − 40 J

ΔU = -70 J

Final answer:

The change in internal energy of the system is calculated using the formula
ΔU = Q - W. With 30 J of thermal energy released and 40 J of work done by the system, the internal energy decreases by 70 J.

Explanation:

Change in Internal Energy Calculation

To calculate the change in internal energy (ΔU) of a system, the first law of thermodynamics is often used, which is expressed as ΔU = Q - W, where Q is the heat added to the system, and W is the work done by the system on its surroundings. In this scenario, Q is a negative value since 30 J of thermal energy is released (or removed) from the system, which makes Q = -30 J. The system does 40 J of work on the surroundings; hence, W is also 40 J.

The change in internal energy is therefore calculated as follows:

ΔU = Q - W
ΔU = (-30 J) - (40 J)
ΔU = -30 J - 40 J
ΔU = -70 J

Thus, the change in internal energy of the system is -70 J, indicating that the internal energy of the system has decreased by 70 joules.

Answer:

E1 =  2996.667N/C E2 = 11237.5N/C

Explanation:

E1 = kQ1/r^2

  =8.99 x 10^9 x 30 x 10^-9/(30x10^-2)^2

  = 2996.667N/C

E2 = kQ2/r^2

      = 8.99 x 10^9 x 50 x 10^-9/(20x10^-2)^2

      = 11237.5N/C

The direction are towards the point a

The amount of  time the shot-put spent in the air before it hits the ground is 3 sec

given the data in the question;

A person throws a shot-put from height, initial height; s = 5ft

Initial vertical velocity or speed; v = 40 ft/s

Now, it is said that, vertical motion model is;

[tex]h = -16t^2 +vt + s[/tex]

so we substitute in the given values

[tex]h = -16t^2 + (40ft/s * t) + 5ft[/tex] --------------Let this be equation 1

To calculate the amount of  time the shot-put spent in the air before it hits the ground.

We say:  height; h = 0 i.e when the shot-put touches the ground, the height becomes zero.

so we substitute in h=0 in equation 1

[tex]0 = -16t^2 + (40ft/s * t) + 5ft[/tex]

we rearrange

[tex]16t^2 - 40t - 5 = 0[/tex]

To solve for "t", we use the quadratic equation

[tex]x = \frac{-b\±\sqrt{b^2-4ac} }{2a} \\[/tex]

as [tex]ax^2 +bx-c = 0[/tex], we take each value from its position and substitute into the quadratic equation

so

a = 16

b = -40

c = -5

so substitute

[tex]x = \frac{-(-40)\±\sqrt{(-40)^2 - (4*16*(-5)} }{2*16} \\\\x = \frac{40\±\sqrt{1600+320} }{32}[/tex]

[tex]x = \frac{40\±\sqrt{1920} }{32}\\so\\\\x = \frac{40+\sqrt{1920} }{32} or \frac{40-\sqrt{1920} }{32} \\\\x = 2.62\\or\\ x = -0.12\\[/tex]

we know that, time can not be negative,

Hence x = 2.62 ≈ 3 sec { nearest tenth }

Therefore, the amount of  time the shot-put spent in the air before it hits the ground is 3 sec

To learn more; https://brainly.com/question/17452424?referrer=searchResults

A) The maximum height is 31.9 m

B) The speed of the ball is 17.7 m/s

Explanation:

A)

We can solve this problem by using the law of conservation of energy. In fact, in abcense of air resistance, the mechanical energy of the ball (sum of potential energy + kinetic energy) must be conserved.

Mathematically:

[tex]U_i +K_i = U_f + K_f[/tex]

where :

[tex]U_i[/tex] is the initial potential energy, at the bottom

[tex]K_i[/tex] is the initial kinetic energy, at the bottom

[tex]U_f[/tex] is the final potential energy, at the top

[tex]K_f[/tex] is the final kinetic energy, at the top

We can rewrite it as

[tex]mgh_i + \frac{1}{2}mu^2 = mgh_f + \frac{1}{2}mv^2[/tex]

where:

m is the mass of the ball

[tex]g=9.8 m/s^2[/tex] is the acceleration of gravity

[tex]h_i = 0[/tex] is the initial height  of the ball

u = 25 m/s is its initial speed

[tex]h_f[/tex] is the maximum height reached by the ball

v = 0 is the final speed (which is zero at the maximum height)

Solving for [tex]h_f[/tex], we find: the maximum height:

[tex]\frac{1}{2}mu^2 = mgh_f\\h_f = \frac{u^2}{2g}=\frac{(25)^2}{2(9.8)}=31.9 m[/tex]

B)

When the ball is halfway up to its maximum height, it means that its height is

[tex]h_f = \frac{31.9}{2}=15.9 m[/tex]

Therefore we can re-apply again the equation of the conservation of energy:

[tex]mgh_i + \frac{1}{2}mu^2 = mgh_f + \frac{1}{2}mv^2[/tex]

where this time v is not zero, but it is the speed of the ball at the height of 15.9 m

Re-arranging the equation and solving for v, we find:

[tex]v=\sqrt{u^2-2gh_f}=\sqrt{25^2-2(9.8)(15.9)}=17.7 m/s[/tex]

Learn more about kinetic energy and potential energy:

brainly.com/question/6536722

brainly.com/question/1198647  

brainly.com/question/10770261  

#LearnwithBrainly

The maximum height the baseball can reach when thrown at an initial speed of 25 m/s is 31.9 meters. When the ball is halfway to this height, its speed is 17.67 m/s.

The subject matter of the question is physics, specifically the concepts of motion, velocity, and gravitational forces.  

Given the initial velocity of the baseball is 25 m/s and the acceleration due to gravity is -9.8 m/s², we can find the maximum height using the equation v² = u² + 2gs, where v is the final velocity, u is the initial velocity, g is acceleration due to gravity, and s is displacement.  

Substituting in the given values gives us 0 = (25 m/s)² + 2*(-9.8 m/s²)*s, so s = (25 m/s)² / (2 * 9.8 m/s²) = 31.9 meters. This is the maximum height the ball reaches.  

When the ball is halfway to its maximum height, it is still subject to the laws of physics, so we cannot simply divide the initial velocity by two. Instead, we can find the velocity at the halfway height (15.95 meters) using the equation v = u + 2gs. Substituting the known values, we get v = sqrt((25 m/s)² + 2*(-9.8 m/s) * (-15.95 m) ) = 17.67 m/s.

https://brainly.com/question/32827736

#SPJ11

The distance travelled in 5 seconds is 125 m

Explanation:

The motion of the skydiver is a free fall motion, since he is acted upon the force of gravity only. Therefore, it is a uniformly accelerated motion, with constant acceleration downward, and we can find the distance he travels by using the following suvat equation:

[tex]s=ut+\frac{1}{2}at^2[/tex]

where

s is the distance travelled

u is the initial velocity

t is the time

a is the acceleration

In this problem, we have:

u = 0 (the skydiver jumps from rest)

[tex]a=g=10 m/s^2[/tex] (acceleration of gravity)

And substituting

t = 5.0 s

we find the distance travelled:

[tex]s=0+\frac{1}{2}(10)(5)^2=125 m[/tex]

Learn more about free fall:

brainly.com/question/1748290

brainly.com/question/11042118

brainly.com/question/2455974

brainly.com/question/2607086

#LearnwithBrainly

Need more details, what is the slope of the line, etc.

It depends.

In order to answer the question, a person has to know:

-- the velocity (speed and direction) of the ball WHEN it's released

-- whether the ball has any net electric charge

-- whether there's any other net electric charge in the neighborhood

-- the mass of the ball, if any net charges are involved

-- what planet is nearest to the ball

-- the acceleration of gravity on that planet

Each of these details has an influence on the answer.  That is, if one of them changes, then the answer changes.  Now, it hasn't escaped my notice that you neglected to provide ANY of this information, so there's no way to even begin to concoct an answer.

Right now, the question is a lot like me asking you "How much will I weigh 8 seconds after I finish eating the steak ?".

Answer:

Energy cannot be created or destroyed.

Explanation:

Energy cannot be created or destroyed, it can only be altered from one from to another.

Answer:

C. Energy cannot be created or destroyed but it can change form.

Energy can be converted from one form to another. The law of conservation of energy says that energy is neither created nor destroyed. When you consume energy, it is not gone forever. Instead, it is changed from one form of energy to another. So, energy is not manufactured and it doesn't go away after you use it. It is just transformed, or stored.

The displacement of the book is 5 meters

Explanation:

The work done by a force when moving an object is given by:

[tex]W=Fd cos \theta[/tex]

where :

F is the magnitude of the force

d is the displacement

[tex]\theta[/tex] is the angle between the direction of the force and the displacement

In this problem, we have:

W = 500 J is the work done by Maria

F = 100 N is the force applied by Maria

[tex]\theta=0^{\circ}[/tex], assuming the direction of the force is parallel to the displacement

So we can rearrange the equation to solve for d, the displacement:

[tex]d=\frac{W}{F cos \theta}=\frac{500}{(100)(cos 0)}=5 m[/tex]

So, the book was moved 5 meters.

Learn more about work:

brainly.com/question/6763771

brainly.com/question/6443626

#LearnwithBrainly

Politics is important as it governs decision making within societies and manages conflict, while political science provides an understanding of these processes and systems, enabling informed citizenship.

Politics and political science are important for several reasons. Firstly, politics is how societies make collective decisions. It determines the distribution of power, resources, and responsibilities within a society. Additionally, politics also manages conflict and ensures social order. Secondly, political science is the systematic study of politics and government. It equips individuals with the knowledge and analytical skills to understand political behavior and policymaking processes, which is essential for informed citizenship.

Through political science, we can understand how different political systems work, compare them, and analyze their impacts on their constituents. Whether intending to participate directly in politics or just wanting to be a well-informed citizen, understanding politics and political science is integral.

https://brainly.com/question/27420052

#SPJ1

Final answer:

Politics and political science are crucial as they determine resource allocation and decision-making within societies. Understanding and participating in politics can shift power toward ordinary people and reflect public interests. Political science uses empirical evidence and analytical tools to interpret political actions and systems.

Explanation:

Importance of Politics and Political Science

Politics and political science are pivotal because they deal with critical questions like who gets what, when, and how. Politics fundamentally addresses the allocation of resources and the mechanisms of decision-making within societies.

Political science is the systematic study of these processes, providing insights into government policies, institutional arrangements, and collective behaviors.

Knowledge in this field empowers citizens to engage meaningfully in their governance and to advocate for fairer, more representative systems.

Citizen engagement is essential for a functioning democracy, as it ensures that the government reflects the public interest. Understanding politics is not just for students at elite universities; it is crucial for all to recognize that political systems and conflicts deeply affect their lives.

Politics is not a spectator sport; active involvement and collective action can shift the balance of power towards ordinary people.

Political science students and scholars endeavor to answer why certain political actors behave as they do and to infer cause-effect relationships from empirical evidence.

The study of politics involves using tools such as probability, statistics, and logic to extract meaningful inferences from qualitative and quantitative data. For faculty, imparting this knowledge to students is a dual task of nurturing civic engagement and fostering academic inquiry into political behaviors and systems.

Answer:

food chain

Explanation:

The given flow chart or diagram represents a food chain . A food chain is the flow of energy from lower level organism to higher level organism.

In ecology, the food chain is the flow of substance and energy from one organism to another in the form of food. Due to the fact that most species consume more than one kind of animal or plant, food chains locally entangle to form a food web.

The main source of food are plants since they use photosynthesis to turn solar energy into food.A flesh-eating animal consumes a plant-eating species in a predator chain. A smaller organism in a parasite chain takes a portion of a larger host and may also become a parasite on itself.

Here, the phytoplanktons are eaten by shrimps and they are in turen eaten by salmon which is edible to humans. Hence, the diagram represents a food chain.

To find more on food chain, refer here:

https://brainly.com/question/16065961

#SPJ2

Answer:

B goes up faster

if x=0, then A=0

if x=1 then B=6

Explanation:

Formulas Or Equations

We have two different formulas

A = 3x

B = 5x + 1.

They both are equations of lines. The number beside the X (coefficient) is also known as the slope of the line. The greater the slope, the faster the function goes up as X increases. We can clearly see that the equation B has a greater slope, which means it goes up faster than A as X increases

When x=0, A=3(0)=0

When x=1, B=5(1)+1=6

Explanation:

(a) The net force in the y direction is the sum of the individual forces.  Taking up to be +y:

∑F = Lift − Weight

∑F = 100,000 N − 75,000 N

∑F = 25,000 N

(b) Since the net force is not 0, the forces are unbalanced.

(c) Since the lift is greater than the weight, the plane will rise.

(d) The net force in the x direction is the sum of the individual forces.  Taking forward to be +x:

∑F = Thrust − Drag

∑F = 200,000 N − 23,000 N

∑F = 177,000 N

(e) Since the net force is not 0, the forces are unbalanced.

(f) Since the thrust is greater than the drag, the plane will accelerate.

Answer:

Explanation:

The force is a vector magnitude, it has direction, course and intensity.

Suppose that you have given two forces at a certain angle and that you need to find the resultant force then you apply the Parallelogram of force low.

You represent the two forces in the drawing as vectors and connect their origin to the same point and then construct a parallelogram over them.

The longer diagonal represents the resultant force.

God is with you!!!

There will be zero radioactive atoms left

Explanation:

The amount of radioactive atoms left of a radioactive sample after a certain time t is given by the equation

[tex]N(t) = N_0 (\frac{1}{2})^{-\frac{t}{\tau}}[/tex]

where

N(t) is the number of radioactive atoms left after time t

[tex]N_0[/tex] is the initial number of radioactive atoms

[tex]\tau[/tex] is the half-life of the sample

In this problem we have:

[tex]N_0 = 800[/tex] (initial number of radioactive atoms)

[tex]t=14 \tau[/tex] (we want to evaluate the number of atoms left after 14 half-lives)

Substituting, we find:

[tex]N(14\tau) = (800)(\frac{1}{2})^{-\frac{14\tau}{\tau}}=0.049[/tex]

This means that there will be zero atoms left, since atoms can't be split in fractional parts.

Learn more about radioactive decay:

brainly.com/question/4207569

brainly.com/question/1695370

#LearnwithBrainly

Answer:

352.8 N

Explanation:

= 36

= 9.8

⁄ = ? = = 36 × 9.8 = 352.8

Answer:

360 N

Explanation:

mass = 36 kg

g = 10m/s²

W = mg

W = 36 × 10

W = 360 N

400 N

The weight of the man is evenly distributed on each scale

The man's total weight of 800-N, when distributed equally over two bathroom scales, will result in each scale reading 400-N.

The man's total weight is 800-N and he is standing on two scales, with his weight distributed evenly. This means each scale will bear half of the total weight. Therefore, the reading on each scale will be 800-N divided by 2. That calculation yields a result of 400-N per scale. So each bathroom scale will show a weight of 400-N, assuming the weight distribution remains equals.

https://brainly.com/question/31878218

#SPJ3

Explanation:

Factors affecting surface tension includes;

There are three factors that affect surface tension.

Temperature- the surface tension of a liquid decreases with increase in temperature.

Soluble impurities - the presence of soluble impurities may increase or decrease the surface tension.

Insoluble impurities- insoluble impurities decrease the surface tension.

Answer:

Humid air is lighter so it has lower pressure

Explanation:B.) humid air is lighter, so it has lower pressure

Explanation:

Humidity is related to air pressure in that, a humid air is lighter and it has very low pressure.

Air is heavier than water vapor.

   The main component of humid air is water vapor.

   Water vapor is mostly water in its gaseous form

   We know that for a single mole of water, the mass is 18g

   Air is a mixture of gases with Nitrogen gas dominating.

   A mole of nitrogen gas has a mass of 28g.

   We can see that air that is humid i.e contains more water vapor is lighter and it has a lower pressure.

the effect of pressure on surface tension can be attributed in part to absorption of gas at the surface of the liquid and in part to an intrinsic decrease in density of the liquid in the neighborhood of the surface.

In the case of liquids , Owing to contact forces between the edge of the surface and the vessel, the surface acquires a curvature, and if the liquid rises up at the edges where it meets the vessel, the pressure will be less in the liquid than in the air, for points just below and just above the surface. The vessel exerts an upward force on the liquid. This is simply a matter of looking at the directions of forces acting, knowing that the surface is under tension.