A 50-cm3 block of wood is floating partially submerged in water, and a 50-cm3 block of iron is totally submerged in water. Which block has the greater buoyant force on it?
A) the wood
B) the iron
C) Both have the same buoyant force.
D) The answer cannot be determined without knowing the densities of the blocks.

Final answer:

All simple machines are variations of the inclined plane or the lever, with examples like the wedge and the wheel and axle. They provide a mechanical advantage by multiplying the force applied. Complex machines, like bicycles, integrate multiple simple machines to increase efficiency.

Explanation:

All simple machines are variations of either the inclined plane or the lever. Two specific examples are the wedge, which is a simple machine consisting of two back-to-back inclined planes, and the wheel and axle, which is a simple machine consisting of a rod fixed to the center of a wheel. These machines help to multiply or augment a force, thereby providing a mechanical advantage to the user.

A complex machine, such as a bicycle or a car, combines several simple machines to perform a task more efficiently. The wire cutters, for instance, combine two levers and two wedges, while bicycles include components like wheel and axles and pulleys. The concept of mechanical advantage (MA) is crucial as it represents the ratio of output to input forces, allowing for a smaller force to perform a given task thanks to the simple machine.

A. Gallium

Using the principle of conservation of angular momentum, we can calculate the final angular velocity of the wheel. The equation for finding this involves the moment of inertia, initial angular velocity, angular acceleration and time.

The final rotational speed of the wheel can be determined through the principles of angular momentum and laws of physics involving rotational motion.

We first find the angular velocity using the equation for conservation of angular momentum, which is given by Linitial = Lfinal where L represents angular momentum. This will involve the moments of inertia and initial angular velocity.

Next, we apply our knowledge of the equation wf = wi + αt, where wf represents the final angular velocity, α stands for angular acceleration and t signifies time. Since the string has been pulled through a certain distance after time 'tl', with t denoting time and 'l' represents the length of string, you can calculate the final angular velocity of the wheel through these variables.

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Final answer:

The final rotational speed (ωfinal) of a wheel after a string is pulled can be found using the conservation of angular momentum, assuming no external torques are present.

Explanation:

The question involves finding the final rotational speed (ωfinal) of a wheel given that a string has been pulled through a distance l after a certain time tl. To answer this, we would need to apply the principles of conservation of angular momentum, assuming there are no external torques acting on the system. The initial angular momentum can be expressed as Linitial = Iinitial ωinitial, and the final angular momentum as Lfinal = Ifinal ωfinal. If the string is wound around the wheel, pulling it would likely change the wheel's moment of inertia. Therefore, to find ωfinal without external torques, we would set Linitial equal to Lfinal and solve for ωfinal.

Answer:

0.8087 C J/g oC

Explanation:

4786 J = 89.0 g x C x (89.5 C- 23.0 C)  

4786 J = 6185.5 gC

0.8087 C J/g oC

0.809 C J/g C (sig figs)

Final answer:

The specific heat of the unknown material, given the provided values, is calculated to be approximately 0.80 J/g°C.

Explanation:

To calculate the specific heat of the unknown material, we use the formula q = mcΔT, where q is the heat absorbed or released (in joules), m is the mass of the substance (in grams), c is the specific heat capacity (in Joules per gram per degree Celsius), and ΔT is the change in temperature (in degrees Celsius).

In this question, q = 4786 joules, m = 89.0 grams, and ΔT (change in temperature) = 89.5°C - 23.0°C = 66.5°C. Plugging in these values, we get 4786 = 89.0 * c * 66.5. Solving for c, we find that c = 4786 / (89.0 * 66.5).

After calculating, the specific heat of the material is found to be approximately 0.80 J/g°C.

Answer:

false

Explanation:

Answer:

option (a)

Explanation:

The electrical power is defined as the energy per unit time.

The formula foe the power is given by

P = V I = I^2 R = V^2 / R

So, to find the power we must know the values of current and voltage.

Answer:

The answer is <<< A. current and voltage

Explanation:

The advantage of using a lever is that it reduces the input force required to lift a heavy object and can alter the direction of the force to be more convenient for the user. Option B is correct.

The advantage of using a lever in lifting heavy objects over lifting them directly is that it reduces the input force required to lift the object. A lever does this by changing the point where the force is applied and by increasing the distance over which this force is applied, making the work of lifting an object easier than lifting it directly. This principle of mechanics falls under the category of simple machines, which are devices that change the direction or magnitude of a force.

In the context of the multiple-choice question provided, the correct answer is : reduces the input force as well as alters the force in a convenient direction. This option accurately reflects the action of a lever—reducing the effort needed to lift a weight (input force) and changing the direction in which the force is applied to be more convenient for the user.

Answer:

B. most gets converted to heat energy

Explanation:

Let us take the example of a car. Though some formula one cars have 50% efficiency, the efficiency of an internal combustion car varies between 18–20%. Though some formula one cars have 50% efficiency This means that more than 80% of energy is not utilized hence it is wasted. Little energy does get converted to sound. But almost no energy changes to light.

So, most gets converted to heat energy.

Answer:

The magnitude of its displacement of the car is 28 km.                

Explanation:

It is given that,

Distance covered by the car due west, [tex]d_1=20\ km[/tex]

Distance covered by the car due south, [tex]d_2=20\ km[/tex]

We need to find the magnitude of its displacement. Let it is given by d. We know that displacement of an object is equivalent to the shortest path traveled. It can be calculated as :

[tex]d=\sqrt{d_1^2+d_2^2}[/tex]

[tex]d=\sqrt{(20)^2+(20)^2}[/tex]

d = 28.28 km

or

d = 28 km

So, the magnitude of its displacement is 20 km. Hence, the correct option is  (c).

The average speed of the ocean current that carried the rubber ducks was approximately 0.309 miles per hour (mi/h) or 0.138 meters per second (m/s), calculated by dividing the total distance by the time taken and converting the units accordingly.

The question revolves around calculating the average speed of ocean currents based on the distance rubber ducks traveled after being spilled into the ocean. To find the average speed, we divide the total distance by the total time taken. In this case, the ducks traveled approximately 1800 miles over eight months. Since one month averages about 30.44 days, and there are 24 hours in a day, we first convert 8 months into hours:

8 months * 30.44 days/month * 24 hours/day = 5825.92 hours

Now we calculate the average speed in miles per hour (mi/h):

Average Speed = Total Distance / Total Time = 1800 miles / 5825.92 hours = 0.309 mi/h

Next, we'll convert this speed into meters per second (m/s), using the conversion factor where 1 mile = 1609.34 meters.

0.309 mi/h * (1609.34 meters/mile) / (3600 seconds/hour) = 0.138 m/s

Therefore, the approximate average speed of the ocean current was 0.309 mi/h or 0.138 m/s.

The final velocity of the snowmobile after accelerating for 5.6 seconds is approximately 8.788 m/s. If it decelerates at a rate of -0.51 m/s^2, it will take roughly 9.22 seconds to reach a complete stop.

To find the final velocity of the snowmobile that has an initial velocity of 4.7 m/s and accelerates at the rate of 0.73 m/s2 for 5.6s, we can use the formula:

v = u + at

Where:

Plugging in the values gives us:

v = 4.7 m/s + (0.73 m/s2)(5.6 s)

v = 4.7 m/s + 4.088 m/s

v ≈ 8.788 m/s

To calculate the time it takes to reach a complete stop when the snowmobile decelerates at a rate of -0.51 m/s2, we rearrange the formula to solve for time:

t = (v - u) / a

Since the final velocity v at a complete stop is 0 m/s, the initial velocity u is 4.7 m/s (the velocity before deceleration), and a is -0.51 m/s2, the time t is:

t = (0 m/s - 4.7 m/s) / -0.51 m/s2

t ≈ 9.22 s

The maximum kinetic energy of the 1.0 kg object suspended from the spring is 0.5 Joules. This is calculated by finding the initial potential energy of the object when it is pulled 0.25 meters downwards which then gets converted to kinetic at equilibrium position.

The student's question relates to the topic of energy in simple harmonic motion, specifically related to the scenario of a mass attached to a spring. The maximum kinetic energy of an oscillating object can be found when the potential energy is at its minimum, which occurs at the equilibrium position. In this case, the maximum kinetic energy is equal to the initial potential energy of the object when it is pulled down.

The initial displacement of the object is 0.25 meters. Therefore, we can find the initial potential energy using the formula U = 0.5 × k × x², where 'U' is the potential energy, 'k' is the spring constant, and 'x' is the displacement. Substituting these values we get U = 0.5 × 16 N/m × (0.25 m)² = 0.5 Joules.

Thus, the maximum kinetic energy of the object is also 0.5 Joules since the entire potential energy at the extreme position will convert into kinetic energy when the object passes through the equilibrium position during its oscillation.

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Answer:

t = 41.56 min

Explanation:

As we know that the distance moved on the trade mill is given as

[tex]d = 7500 ft[/tex]

here we know that

[tex]1 ft = 12 inch[/tex]

[tex]1 inch = 2.54 cm[/tex]

so we have

[tex]1 ft = 12 \times 2.54 cm[/tex]

[tex]1 ft = 0.3048 m[/tex]

now we know that

[tex]d = 7500 \times 0.3048 m[/tex]

[tex]d = 2286 m[/tex]

now we know that the speed on the trade mill is given as

[tex]v = 55 m/min[/tex]

so time taken to move the given distance is

[tex]t = \frac{d}{v}[/tex]

[tex]t = \frac{2286}{55}[/tex]

[tex]t = 41.56 min[/tex]

Answer:

100 plus charges

Explanation:

A neutral charge is the one that it's not positive (plus sign) neither negative(minus sign), it is 0. So, if there is a -100 charge, to the total charge be neutral, it's necessary to add a positive charge at the same amount, which would be +100.

The momentum of the object-Earth system remains the same as the object falls. The recoil of the Earth is negligible but present, ensuring conservation of momentum within the closed system.

As an object falls freely toward the Earth, the momentum of the object-Earth system remains the same. To understand this, we need to consider the laws of conservation of momentum, which state that within a closed system, momentum does not change. When an object, such as a ball, falls and collides with the Earth, there is an equal and opposite change in momentum of the Earth, maintaining the system's total momentum. Although the Earth's recoil is imperceptibly small due to its large mass, it is still present.

For example, if a superball collides with the ground, the change in momentum of the superball will be equal in magnitude and opposite in direction to Earth's change in momentum. This is because, in a closed system, the sum of the forces is zero, leading to no net change in momentum. Similarly, when considering two cars in a collision where friction is negligible, the total momentum before and after the collision remains the same.

In summary, when considering a sufficiently large system, such as an object-and-Earth system, the law of momentum conservation implies that the total momentum remains constant, even if individual components within that system change momentum.