A street light is on top of a 8 foot pole. Joe,
who is 4 feet tall, walks away from the pole at
a rate of 4 feet per second. At what speed is
the tip of Joe’s shadow moving from the base
of the pole when he is 13 feet from the pole?
The speed of the tip of Joe’s shadow moving from the base of the pole when he is 13 feet from the pole is 8 m/s.
What is speed?Speed is defined as the SI unit of speed is measured in milliseconds per second, or m/s. It is the ratio of distance with time.
It is defined as a measurement of the length of time it takes for an object to travel a certain distance.
It can also be defined as the speed at which an object's location changes in any direction.
There are four types of speed.
Uniform speedVariable speedAverage speedInstantaneous speed8/4 = y/y-x
8y - 8x = 4y
y = 2x
y = 2 x 4
y = 8
Thus, the speed of the tip of Joe’s shadow moving from the base of the pole when he is 13 feet from the pole is 8 m/s.
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Which energy transformations occur when a candle burns?
Answer:
Chemical energy into Thermal energy and Light Energy
Explanation:
When candle is burnt then its wax which is a having chemical potential energy in it will burn and convert its chemical potential energy into light energy and thermal energy.
So here the wax will melt down after burning and few of its part will evaporate and convert its energy into thermal energy and light energy both.
So overall if we write energy transformation in this
Chemical potential energy of wax = Light Energy + Thermal energy
What is the value of the normal force if the coefficient of kinetic friction is 0.22 and the kinetic frictional force is 40 newtons?
The value of the normal force if the coefficient of kinetic friction is 0.22 and the kinetic frictional force is 40 Newtons would be 181.81 Newtons.
What is friction?The friction force prevents any two surfaces of objects from easily sliding over each other or slipping across one another. It depends upon the force applied to the object.
As given in the problem we have to find the value of the normal force if the coefficient of kinetic friction is 0.22 and the kinetic frictional force is 40 newtons,
Friction force =(coefficient of friction)*Normal force
40 = 0.22* Normal force
Normal Force = 40/0.22
=181.81 Newtons
Thus, the normal force comes out to be 181.81 Newtons.
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The velocity v of the flow of blood at a distance "r" from the central axis of an artery of radius "R" is: v = k(R^2^ - r^2^) where k is the constant of proportionality. Find the average rate of flow of blood along a radius of the artery. (use 0 and R as the limits of integration) ...?
Final answer:
The average rate of flow of blood along the radius of an artery is found by integrating the velocity equation v = k(R² - r²) from 0 to R, which results in an average velocity formula of (2/3)kR after integration and simplification.
Explanation:
The question asks to find the average rate of flow of blood along a radius of the artery using the given velocity equation v = k(R² - r²) and integrating between the limits 0 and R. To find the average velocity, we integrate the given equation across the artery's radius and then divide by the radius R to calculate the average.
The integration process involves calculating the integral of k(R² - r²) with respect to r, over the interval from 0 to R, which gives us kR²r - (kr³)/3 evaluated between 0 and R. Substituting the limits and simplifying, the result is (2/3)kR². To find the average velocity, we divide this by R, resulting in an average velocity of (2/3)kR.
Which of the following best describes the difference between speed and acceleration?
A.
Speed is the distance an object travels within a specific unit of time, whereas acceleration is the rate at which the speed or direction of an object is changing.
B.
Acceleration is the distance an object travels within a specific unit of time, whereas speed is the rate at which the acceleration or direction of an object is changing.
C.
Speed is the distance an object travels within a specific unit of time, whereas acceleration is a measure of the force necessary to change the speed of an object.
D.
Acceleration is the distance an object travels within a specific unit of time
Answer:
A. Speed is the distance an object travels within a specific unit of time, whereas acceleration is the rate at which the speed or direction of an object is changing.
Explanation:
Speed is the distance an object travels within a specific unit of time. The average speed of an object can be calculated by dividing distance over time. Acceleration, on the other hand, is the rate at which the speed or direction of an object is changing. Acceleration can be positive or negative.
Audio frequency range of a human ear is 20Hz - 20000 Hz. Express the range in terms of time period ? Answer needed urgently. Pl. help. Thanks ! S.Ramya ...?
The figure below shows an acceleration-versus-force graph for three objects pulled by rubber bands. The mass of object 2 is 0.20 kg. What are the masses of objects 1 and 3?
Without the graph, we can't calculate the exact masses. However, by finding the slope of the line representing each object on a force-versus-acceleration graph, and using Newton's Second Law (F=ma), we can solve for the objects' masses.
Explanation:The question refers to an acceleration-versus-force graph for three objects but unfortunately no graph was provided. However, in order to calculate the mass of the objects from an acceleration-versus-force graph, we could potentially use Newton's Second Law (F = ma), where F is the force, m is the mass, and a is the acceleration. Here's how it would be done:
For each object, find the slope of the line connecting it to the origin. The slope will give you the acceleration of the object.If you are given the force (F), use Newton's Second law to solve for mass (m).Note that if you see a higher slope for one object compared to another, it means that the object has a lesser mass, because a lesser mass will lead to a greater acceleration under the same force.Learn more about Physics here:https://brainly.com/question/32123193
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The masses of objects 1 and 3 are 0.25 kg and 1.5 kg, respectively.
To find the masses of objects 1 and 3, we can use Newton's second law of motion, which states that force is equal to mass times acceleration:
F = ma
We can rewrite this equation to solve for mass:
m = F / a
Step 1: Find the slope of the line for each object
The slope of a line is equal to rise over run. In an acceleration-versus-force graph, the rise is the acceleration and the run is the force.
For object 1, the slope of the line is 4a / 1 = 4a. This means that object 1 has an acceleration of 4a for every 1 unit of force.
For object 2, the slope of the line is 3a / 2 = 1.5a. This means that object 2 has an acceleration of 1.5a for every 1 unit of force.
For object 3, the slope of the line is 2a / 3 = 0.67a. This means that object 3 has an acceleration of 0.67a for every 1 unit of force.
Step 2: Calculate the mass of each object
Now that we know the acceleration of each object, we can use Newton's second law to calculate their masses.
Mass of object 1:
m1 = F / a1 = 1 / 4a = 0.25 kg
Mass of object 2:
m2 = F / a2 = 1 / 1.5a = 0.67 kg
Mass of object 3:
m3 = F / a3 = 1 / 0.67a = 1.5 kg
Conclusion
The masses of objects 1 and 3 are 0.25 kg and 1.5 kg, respectively.
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Let v(t)=t^2−3t be the velocity, in feet per second, of an object at time t, in seconds.
a) What is the initial velocity? ___ ft/sec
b) When does the object have a velocity of zero? If there is more than time, list all answers in a comma separated list. ___ seconds
The initial velocity of the object is 0 ft/sec. The points in time when the object has a velocity of zero are at t=0 and t=3 seconds.
Explanation:To answer these questions, it's important to understand what the variables represent in this equation. The object's velocity is given by v(t)=t^2−3t where v is the velocity in feet per second and t is the time in seconds.
a) The initial velocity is the velocity of the object at the start, which means at time t=0. By substituting t=0 in the equation, we obtain v(0)=(0)^2 - 3(0) = 0 feet/sec.
b) The object has a velocity of zero when v(t) = 0. In other words, we need to solve the equation t^2−3t = 0 for t. Factoring, we get t(t - 3) = 0, thus t = 0, 3 seconds are the moments at which the object's velocity is zero.
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Democritus thought that matter was made of tiny particles
A. of earth, air, fire, and water.
B. that could not be divided.
C. that could be divided.
D. that were all round and smooth.
Correct answer choice is :
B) That could not be divided.
Explanation:
Democritus was a Greek scholar who lived within 470-380 B.C. He elaborated the theory of the atom, Greek for permanent. Democritus thought that everything in the world was made up of atoms, which were tiny and durable. They assumed that matter was made up of very small particles. They named these particles atoms, which comes from an antique Greek word signifying permanent. These atoms were supposed to be absolutely indivisible and forever.
What is the milky way?;
Our galaxy, the Milky Way, appears to be a band of stars in the sky, but it's actually a disk. Hundreds of billions of stars are clumped into lines called spiral arms. Earth is located about half-way between the center of the Milky Way and its outer edge.
according to newton's first law of motion what is required to make an object slow down
According to Newton's first law of motion, an object at rest will remain at rest and an object in motion will continue moving at a constant velocity unless acted upon by an external force. To make an object slow down, an external force in the opposite direction of its motion, such as friction, is required.
Explanation:According to Newton's first law of motion, an object will continue moving at a constant velocity unless acted upon by an external force. To make an object slow down, an external force in the opposite direction of its motion is required. This force is called friction. Friction can be caused by various factors, such as air resistance or contact with a surface.
Learn more about Newton's first law of motiona particle moves along a straight line OX. at a time t(in seconds) the distance X(in metres) from the particle O is given by x=40+12t-t3. how long would the particle travel before coming to rest ...?
Answer:
16m
Explanation:
What two organelles should be labeled that WOULD NOT be found in an animal cell?
The acceleration due to gravity on Earth is 9.80 m/s2. An African elephant can have a mass up to 6,050 kg. What is its weight?
The weight of an object is calculated by multiplying its mass by the acceleration due to gravity. With the mass of the African elephant as 6050 kg and Earth's gravity at 9.80 m/s², the elephant's weight would be 59,290 Newtons.
Explanation:The weight of an object is the force exerted on it due to gravity. It can be calculated using the formula Weight = Mass × Gravity. In this case, the mass of the African elephant is given as 6,050 kg, and the acceleration due to gravity on Earth is 9.80 m/s².
Thus by multiplying the mass of the elephant with the acceleration due to gravity, we get: Weight = 6,050 kg × 9.80 m/s² = 59,290 N. So the weight of the African elephant on Earth would be 59,290 Newtons.
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Which of the following is distance divided by the change in time?
displacement
acceleration
speed
velocity
Answer:
the correct answer is speed, velocity scored incorrectly on my quiz
Explanation:
Which of the following forms of radiation can be shielded by earths atmosphere? Gamma rays,radio waves,visible light, all of the above A. Rob.
The Earth's atmosphere can shield against various forms of electromagnetic radiation, mostly blocking gamma rays and allowing radio waves and visible light to penetrate. Thus, gamma rays are the form of radiation primarily shielded by our atmosphere.
The Earth's atmosphere provides a natural shield against various forms of electromagnetic radiation, including gamma rays, X-rays, and ultraviolet (UV) light. These types of radiation pose a potential risk to living organisms due to their high energy levels. However, while the atmosphere blocks most gamma rays and X-rays, completely shielding against all electromagnetic radiation is a different matter.
The atmosphere does allow visible light to pass through, enabling us to see the world around us. Radio waves, especially those on the lower frequency end, can also penetrate the atmosphere, which is why we can receive radio signals. On the other hand, gamma rays, which have the shortest wavelength and highest energy, are indeed absorbed by the atmosphere. This absorption is critical for protecting life on Earth from their potentially harmful effects.
To clarify: Gamma rays are mostly absorbed by the atmosphere, radio waves can generally penetrate it, and visible light travels through it to reach the Earth's surface. Therefore, the correct answer to the question about which form of radiation can be shielded by Earth's atmosphere is primarily gamma rays. However, it's worth noting that the question wording implies all of them can be 'shielded' to an extent, but gamma rays are the ones that are most effectively blocked.
A cyclist maintains a constant velocity of
4 m/s headed away from point A. At some
initial time, the cyclist is 253m from point A.
What will be his displacement from his
starting position after 64 s?
Answer in units of m
What will be his position from point A after
that time?
Answer in units of m
The cyclist's displacement from the starting position after 64 seconds is 256 meters. Their position from point A after that time is 509 meters.
Explanation:If a cyclist maintains a constant velocity of 4 m/s headed away from point A, their displacement after any given time can be calculated using the formula Δx = vt, where Δx is the displacement, v is the velocity, and t is the time. For a time of 64 seconds, the displacement would be Δx = (4 m/s) × (64 s) = 256 meters.
Since the cyclist starts 253 meters away from point A, the new position (total distance from point A) after 64 seconds can be found by adding the initial distance to the displacement. This gives us a total distance = 253 m + 256 m = 509 meters from point A.
All waves consist of a continuous series of _____.
pulses
circles
compressions
rarefactions
Answer: The correct answer is pulses.
Explanation:
Wave is a disturbance which carries energy from one particle to another. Wave is a continuous disturbance.
Pulse is a single disturbance. It travels through one point to another.
Sound wave consists of rarefaction and compression. It need medium to travel.
In the circular wave, the particles move both parallel and perpendicular to the motion of the wave.
Therefore, all waves consist of a continuous series of the pulses.
When heat flows from one substance to another, what happens to the temperature of the substance giving off the heat and to the temperature of the substance receiving the heat?
Heat transfer from one substance to another results in the decrease of temperature in the substance losing heat and an increase in the substance gaining heat. At the melting or boiling points, heat absorbed is used for phase changes instead of raising the temperature. The heat required for a phase change is proportional to the substance's mass.
When heat flows from one substance to another, this process is known as heat transfer. The substance giving off heat, or the higher temperature substance, will experience a decrease in its temperature. Conversely, the substance receiving the heat, or the cooler substance, will see an increase in temperature. This heat transfer continues until both substances reach thermal equilibrium, meaning they have the same temperature.
Specifically, at the melting point or boiling point, heat flow into a substance does not change its temperature but rather is used to change its state. This is because the energy is utilized to break the intermolecular forces that hold the substance in its current phase. For example, when ice melts to become water at its melting point, the temperature remains constant until all the ice has melted. The same is true for boiling; the temperature of the liquid remains constant during the transition to a gas.
The amount of heat required for these phase changes is directly proportional to the mass of the substance undergoing the change. In other words, larger amounts of substance will require more heat to complete the phase transition.
A car has a mass of 1,200 kg. What is its acceleration when the engine exerts a force of 600 N? (Formula: F=ma) 0.5 m/s2 2 m/s2 600 m/s2 1,800 m/s2
As per the question the car has a mass of 12,00 kg.
The engine exerts a force of 600 N. [ here newton i.e N is the unit of force]
We are asked to calculate the acceleration of the particle .
From Newton's second law of motion we know that force acting on a particle is mass times the acceleration of the particle . Mathematically it can be written as-
F = ma [Here F is the applied force,m is the mass which is constant here and ' a' is the acceleration]
Here m =1200 kg
F = 600 N
Hence the acceleration produced due to the force exerted by the engine on car is-
[tex]a =\frac{F}{m}[/tex]
[tex]=\frac{600 N}{1200 kg}[/tex]
[tex]=0.5 m/s^2[/tex] [ans]
A push or pull that gives energy to an ob-
ject, causing that object to start moving, stop
moving, or change its motion is
1. friction.
2. pressure.
3. inertia.
4. a force. ...?
Which substance in Table 5.2 requires the smallest amount of energy to increase the temperature of 51.5g of that substance by 10K ?
All of these are specific heats of some substances at 298 K.
So N2(g) is 1.04 J/g-k
Al (s) .90 J/g-k
Fe (s) .45 J/g-k
Hg (l) .14J/g-k
H2O (l) 4.18 J/g-k
CH4 (g) 2.20 J/g-k
CO2 (g) .84 J/g-k
CaCO3 (s) .82 J/g-k
What do tennis and volleyball have in common?
Continental climates have _______ summers and ________ winters.
warm; cold
cool; cool
warm; warm
cool; warm
Answer:
Continental climates have WARM summers and COLD winters. People who live with areas that experience continental climates must be prepared for the seasonal changes.
Explanation:
Static, sliding and rolling are types of friction true or false
The stress force that causes a mass of rock to pull or twist in opposite directions in called ______.
Shearing
The stress force that causes a mass of rock to pull or twist in opposite directions is called shearing.
Hope this helps! :)
Which of the following best illustrates the role that gravity played in the formation of our solar system?
A. Gravity allowed the nebula to expand and move outward.
B. Gravity caused the nebula to cool enough for planets to form.
C. Gravity removed excess gas and dust from the cores of the planets.
D. Gravity pulled particles of dust and gas together to form planets.
Answer:
Option D
Explanation:
Gravity is a force of attraction by virtue of mass of a body. It is an attractive force. It is due to gravity that the planets and hence, the solar system was formed. Starting from the nebula, the gravity caused the nebula to contract and form start. From rest of the material, the dust and gas were pulled in together due to gravity to form planet. The gravity of the Sun holds the planets in their respective orbits.
Thus, option D is correct.
Brittany is changing the tire of her car on a steep hill 22.4 m high. She stumbles and drops the 10.5-kg spare tire, which rolls down the hill, starting with an initial speed of 2.10 m/s.
What is the speed of the tire at the top of the next hill, which is 8.59 m high?
The speed of the tire at the top of the next hill, which is 8.59 m high, is approximately 15.12 m/s.
a) Variables:
- [tex]\( h_1 \)[/tex] = Initial height of the hill (22.4 m)
- [tex]\( h_2 \)[/tex] = Height of the next hill (8.59 m)
- [tex]\( v_{i1} \)[/tex] = Initial speed of the tire (2.10 m/s)
-[tex]\( v_{f1} \)[/tex] = Final speed at the top of the first hill
- [tex]\( v_{f2} \)[/tex] = Final speed at the top of the next hill
- g = Acceleration due to gravity (-9.8 m/s²)
b) Equation for the first hill:
[tex]\[ v_{f1}^2 = v_{i1}^2 + 2gh_1 \][/tex]
c) Calculate [tex]\( v_{f1} \)[/tex]:
[tex]\[ v_{f1}^2 = (2.10 \, \text{m/s})^2 + 2(-9.8 \, \text{m/s}^2)(22.4 \, \text{m}) \][/tex]
[tex]\[ v_{f1} \approx 16.83 \, \text{m/s} \][/tex]
d) Equation for the next hill:
[tex]\[ v_{f2}^2 = v_{f1}^2 + 2gh_2 \][/tex]
e) Solve for [tex]\( v_{f2} \)[/tex]:
[tex]\[ v_{f2}^2 = (16.83 \, \text{m/s})^2 + 2(-9.8 \, \text{m/s}^2)(8.59 \, \text{m}) \][/tex]
[tex]\[ v_{f2} \approx 15.12 \, \text{m/s} \][/tex]
The speed of the tire at the top of the next hill, which is 8.59 m high, is approximately 15.12 m/s.
Final answer:
The speed of the tire at the top of the next hill is 21.2 m/s.
Explanation:
To find the speed of the tire at the top of the next hill, we can use the principle of conservation of energy.
According to the principle of conservation of energy, the initial potential energy of the tire at the top of the first hill is equal to the final potential energy of the tire at the top of the next hill.
Therefore, we have:
mgh = 1/2 × mv²
Where m is the mass of the tire, g is the acceleration due to gravity, h is the height difference between the two hills, and v is the final velocity of the tire at the top of the next hill.
Plugging in the values, we get:
10.5 × 9.8 × 22.4 = 1/2 × 10.5 × v²
Solving for v, we find:
v = sqrt((2 × 10.5 × 9.8 × 22.4) / 10.5)
v = 21.2 m/s
A sled and rider, gliding over horizontal, frictionless ice at 4.7 m/s , have a combined mass of 80 kg . The sled then slides over a rough spot in the ice, slowing down to 3.4 m/s . What impulse was delivered to the sled by the friction force from the rough spot? Express your answer to two significant figures and include the appropriate units.
A speeding car collides with a wall (attached to Earth). Consider the car-Earth system to be isolated. A loud sound is produced in the collision, and the car is deformed. What can you say about the momentum of the car-Earth system in this case? ...?
Answer:
A. The total momentum of the system is conserved.