Question 1

Suppose a soap box car is coasting on a track (no motor; no brake), moving from left to right, and part of the track is shown below. Friction /air resistance is present and the car comes to a stop at point E.
 
-Please identify points of maximum and minimum potential energy, if any.

Accepted Answer

The answer of Suppose a soap box car is coasting...

Question 2

Suppose a soap box car is coasting on a track (no motor; no brake), moving from left to right, and part of the track is shown below. Friction /air resistance is present and the car comes to a stop at point E.
 
-Please identify points of maximum and minimum total energy, if any.

Accepted Answer

The answer of Suppose a soap box car is coasting...

Question 3

Like a baseball bat, a tennis racket has a sweet spot at its center of percussion. If a tennis ball hits this center of percussion, the racket's handle does not accelerate. This is because

Accepted Answer

The center of percussion is the point where the linear and angular motions of the racket cancel each other out at the handle, resulting in no acceleration felt at the handle.

Question 4

You go through a loop in a roller coaster at constant speed. Where is your apparent weight a minimum?

Accepted Answer

At the top of the loop, the centripetal force required to keep you moving in a circle is provided entirely by gravity, reducing the normal force exerted by the seat on you to its minimum. This makes your apparent weight the lowest at this point.

Question 5

You are riding a very fast Ferris Wheel so that you actually notice a variation in your apparent weight. Where is your apparent weight maximum?

Accepted Answer

Your apparent weight is maximum at the bottom of the Ferris wheel because the normal force exerted by the seat (which constitutes your apparent weight) is greatest there due to the centripetal acceleration being directed upwards, adding to the effect of gravity.

Question 6

You are riding an amusement park ride where you are strapped to the inside of a giant metal wheel that is rotating quite rapidly. Your acceleration is

Accepted Answer

Your acceleration is toward the center of the wheel due to centripetal acceleration, which always points towards the center of the circle in circular motion.

Question 7

You go to an amusement park and, being in a physics class, you have connections. The management lets you stand on a scale as you ride a Ferris Wheel that rotates fairly rapidly. You will notice the lowest reading on the scale

Accepted Answer

CWhen you're on top of the Ferris wheel, the normal force (the force the scale exerts on you) is weaker than your weight because the centripetal force needed to keep you in circular motion is directed downwards, reducing the normal force. When you're at the bottom, the normal force is stronger than your weight because it must support your weight and provide the centripetal force directed towards the center of the circle, which in this case is upwards from your perspective. However, the question asks for the lowest reading on the scale, which corresponds to when the normal force is weakest, i.e., at the top. Therefore, the correct explanation is that the lowest reading occurs on top due to the normal force being weaker than your weight, making choice A correct and choice C incorrect in the context of the question's actual request for the lowest reading.

Question 8

You go to an amusement park and, being in a physics class, you have connections. The management lets you stand on a scale as you ride a Ferris Wheel that rotates fairly rapidly. You will notice the highest reading on the scale

Accepted Answer

When you're at the bottom of the Ferris wheel, the normal force exerted by the scale on you must not only support your weight but also provide the centripetal force needed to keep you moving in a circle. This results in a higher scale reading at the bottom.

Question 9

You are on an airplane waiting to take off for a summer trip. Having just come from your physics final, you decide to measure the acceleration of the plane during takeoff by tying your graphing calculator to a string and suspending it. Your new device will do a great job of measuring the plane's constant acceleration during takeoff because, as the plane accelerates your calculator will

Accepted Answer

When the plane accelerates forward, the calculator (acting as a pendulum) will swing backward due to inertia. It will stay in that position relative to the plane, indicating the plane's constant forward acceleration.

Question 10

The curves on bicycle racetracks are steeply banked, so that the inner edge of each curve is much lower than its outer edge. This banking tips the support force that the track exerts on the bicycle wheel toward the center of each turn. That center-directed or centripetal force on the bicycle is important because it

Accepted Answer

The centripetal force is crucial for changing the direction of the bicycle's velocity towards the center of the curve, allowing it to complete the turn without skidding. This force does not do work on the bicycle, as work requires a component of force in the direction of motion, and in this case, the centripetal force is perpendicular to the motion, not increasing or decreasing the bicycle's energy.

Question 11

You are flying on an airplane and you notice that a ball of aluminum foil from lunch starts to roll to the left. From the motion of the foil ball you can conclude that the plane is

Accepted Answer

The ball rolls to the left due to inertia as the plane turns to the right, causing the ball to move in the opposite direction of the turn.

Question 12

Some engineers have suggested that we can simulate gravity in outer space by having a circular rotating space station where persons feel an outward - directed fictitious force due to the rotation of the station. The reason they feel such a force is because

Accepted Answer

The correct answer is C because when a space station rotates, the people inside are accelerating toward the center due to the centripetal force. However, their inertia (the tendency of an object to resist changes in its state of motion) makes them feel as though they are being pushed outward, simulating gravity. This is a result of their bodies wanting to continue moving in a straight line (tangentially to the circle) while the station's rotation pulls them inward.

Question 13

A classroom demo that is popular with students and unpopular with custodians is to fill a Styrofoam cup with water, poke a hole in the bottom and then drop the cup into a garbage can waiting below. On the way down, the leak will

Accepted Answer

The leak stops because both the cup and the water are in free fall, making them locally weightless. This means the water doesn't exert pressure on the hole as it would if the cup were stationary, stopping the leak.

Question 14

The spin cycle in your washing machine partially dries clothes by spinning them in a perforated metal basket. Such a process works because

Accepted Answer

The spin cycle works by creating a centrifugal force that pushes the water outward through the perforations in the basket. This force acts perpendicular to the axis of rotation, causing the water to leave the basket moving tangent to the circular path it follows inside the basket.

Question 15

You are swinging a tin can around your head in a perfectly horizontal circle of radius 4 m. (This is really not possible but we're saying it almost happens.) If the speed of the can is 4 m/s and its mass is 2 kg, what inward force is required to keep the can moving in the circle?

Accepted Answer

The answer of You are swinging a tin can around...

Question 16

You are swinging a tin can around your head in a perfectly horizontal circle of radius 4 m. (This is really not possible but we're saying it almost happens.) If the speed of the can is 4 m/s what is its acceleration?

Accepted Answer

The answer of You are swinging a tin can around...

Question 17

You are swinging a tin can around your head in a perfectly horizontal circle of radius 4 m. (This is really not possible but we're saying it almost happens.) If you exert a force of 9 N and the mass of the can is 1 kg, with what speed is the can moving around the circle?

Accepted Answer

The force exerted to maintain circular motion is given by the centripetal force formula $F = \frac{mv^2}{r}$, where $F$ is the force, $m$ is the mass, $v$ is the velocity, and $r$ is the radius. Rearranging for $v$, we get $v = \sqrt{\frac{Fr}{m}}$. Substituting the given values, $v = \sqrt{\frac{9 \times 4}{1}} = \sqrt{36} = 6$ m/s.

Question 18

A person is swinging a tin can around in a vertical circle at a constant speed. Please identify the points, if any, of
-maximum/ minimum kinetic energy

Accepted Answer

The answer of A person is swinging a tin can...

Question 19

A person is swinging a tin can around in a vertical circle at a constant speed. Please identify the points, if any, of
-maximum/ minimum potential energy

Accepted Answer

The answer of A person is swinging a tin can...

Question 20

A person is swinging a tin can around in a vertical circle at a constant speed. Please identify the points, if any, of
-maximum/ minimum total mechanical energy

Accepted Answer

The answer of A person is swinging a tin can...

Quiz 3: Mechanical Objects, Part 1

Suppose a soap box car is coasting on a track (no motor; no brake), moving from left to right, and part of the track is shown below. Friction /air resistance is present and the car comes to a stop at point E. -Please identify points of maximum and minimum potential energy, if any.

Suppose a soap box car is coasting on a track (no motor; no brake), moving from left to right, and part of the track is shown below. Friction /air resistance is present and the car comes to a stop at point E. -Please identify points of maximum and minimum total energy, if any.

Like a baseball bat, a tennis racket has a sweet spot at its center of percussion. If a tennis ball hits this center of percussion, the racket's handle does not accelerate. This is because

You go through a loop in a roller coaster at constant speed. Where is your apparent weight a minimum?

You are riding a very fast Ferris Wheel so that you actually notice a variation in your apparent weight. Where is your apparent weight maximum?

You are riding an amusement park ride where you are strapped to the inside of a giant metal wheel that is rotating quite rapidly. Your acceleration is

You go to an amusement park and, being in a physics class, you have connections. The management lets you stand on a scale as you ride a Ferris Wheel that rotates fairly rapidly. You will notice the lowest reading on the scale

You go to an amusement park and, being in a physics class, you have connections. The management lets you stand on a scale as you ride a Ferris Wheel that rotates fairly rapidly. You will notice the highest reading on the scale

You are flying on an airplane and you notice that a ball of aluminum foil from lunch starts to roll to the left. From the motion of the foil ball you can conclude that the plane is

Some engineers have suggested that we can simulate gravity in outer space by having a circular rotating space station where persons feel an outward - directed fictitious force due to the rotation of the station. The reason they feel such a force is because

A classroom demo that is popular with students and unpopular with custodians is to fill a Styrofoam cup with water, poke a hole in the bottom and then drop the cup into a garbage can waiting below. On the way down, the leak will

The spin cycle in your washing machine partially dries clothes by spinning them in a perforated metal basket. Such a process works because

You are swinging a tin can around your head in a perfectly horizontal circle of radius 4 m. (This is really not possible but we're saying it almost happens.) If the speed of the can is 4 m/s and its mass is 2 kg, what inward force is required to keep the can moving in the circle?

You are swinging a tin can around your head in a perfectly horizontal circle of radius 4 m. (This is really not possible but we're saying it almost happens.) If the speed of the can is 4 m/s what is its acceleration?

You are swinging a tin can around your head in a perfectly horizontal circle of radius 4 m. (This is really not possible but we're saying it almost happens.) If you exert a force of 9 N and the mass of the can is 1 kg, with what speed is the can moving around the circle?

A person is swinging a tin can around in a vertical circle at a constant speed. Please identify the points, if any, of -maximum/ minimum kinetic energy

A person is swinging a tin can around in a vertical circle at a constant speed. Please identify the points, if any, of -maximum/ minimum potential energy

A person is swinging a tin can around in a vertical circle at a constant speed. Please identify the points, if any, of -maximum/ minimum total mechanical energy