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Intermediate
Mathematical
MCQ

A block rests on a flat plane inclined at an angle of \(30^\circ\) with respect to the horizontal. What is the minimum coefficient of friction necessary to keep the block from sliding?

Intermediate
Proportional Analysis
GQ

The Earth’s radius is \(6.37 \times 10^{6} \, \text{m}\). What is the radius of a planet that has the same mass as Earth but on which the free-fall acceleration is \(5.50 \, \text{m/s}^2\)?

Intermediate
Conceptual
MCQ
A side view diagram showing a uniform rod of length L pivoted at its upper left end. The rod is positioned at an angle of 45 degrees below the horizontal. A dashed horizontal reference line is drawn through the pivot point. An arc-shaped arrow indicates the clockwise motion of the rod towards the vertical. The pivot point is represented by a small filled circle.

A uniform rod of length \( L \) is pivoted at one end \(45^{\circ}\) below the horizontal and released from rest. The rod swings freely downward. Which of the following best describes the angular acceleration of the rod as it swings from the initial position to the vertical position?

Advanced
Mathematical
GQ

Block 2 initially is at rest. Block 1 travels towards block 2 and collides with Block 2 as shown above. Find the final velocities of both blocks assuming the collision is elastic.

Advanced
Proportional Analysis
MCQ

A \(250 \, \text{newton}\) centripetal force acts on a car moving at a constant speed in a horizontal circle. If the same force is applied, but the radius is made smaller, what happens to the speed \(v\) and the frequency \(f\) of the car?

Intermediate
Conceptual
MCQ

Which of the following best explains why astronauts experience weightlessness while orbiting the earth?

Intermediate
Proportional Analysis
GQ

Two identical arrows, one with \( 2 \) times the speed of the other, are fired into a bale of hay. Assuming the hay exerts a constant “frictional” force on the arrows, the faster arrow will penetrate how much farther than the slower arrow?

Intermediate
Mathematical
FRQ

An adult exerts a horizontal force on a swing that is suspended by a rope of length \( L \), holding it at an angle \( \theta \) with the vertical. The child in the swing has a weight \( W \) and dimensions that are negligible. In terms of \( W \) and \( \theta \), determine:

Intermediate
Mathematical
GQ

A rescue plane wants to drop supplies to isolated mountain climbers on a rocky ridge that is \( 235 \) \( \text{m} \) below. The plane is traveling horizontally with a speed of \( 250 \) \( \text{km/h} \). How far in advance of the recipients (horizontal distance) must the goods be dropped?

Advanced
Mathematical
GQ

A car is traveling 20 m/s when the driver sees a child standing on the road. She takes 0.8 s to react then steps on the brakes and slows at 7.0 m/s2. How far does the car go before it stops?

Intermediate
Mathematical
FRQ

A geologist suspects that her rock specimen is hollow, so she weighs the specimen in both air and water. When completely submerged, the rock weighs twice as much in air as it does in water.

Advanced
Mathematical
MCQ

The elliptical orbit of a comet is shown above. Positions \(1\) and \(2\) are, respectively, the farthest and nearest positions to the Sun, and at position \(1\) the distance from the comet to the Sun is \(10\) times that at position \(2\). What is the ratio \(\dfrac{F_1}{F_2}\), the force on the comet at position \(1\) to the force on the comet at position \(2\)?

Advanced
Mathematical
GQ

A \(3800 \, \text{kg}\) open railroad car coasts along with a constant speed of \(8.60 \, \text{m/s}\) along a level track. Snow begins to fall vertically and fills the car at a rate of \(3.50 \, \text{kg/min}\). Ignoring friction with the tracks, what is the speed of the car after \(90 \, \text{min}\)?

Beginner
Conceptual
MCQ

Consider an object on a rotating disk at a distance \( r \) from its center, held in place on the disk by static friction. Which of the following statements is not true concerning this object?

Intermediate
Mathematical
GQ

Two objects (49.0 and 24.0 kg) are connected by a massless string that passes over a massless, frictionless pulley. The pulley hangs from the ceiling. Find the acceleration of the objects and the tension in the string.

Advanced
Mathematical
MCQ
Wagon Wheel Structure Moment of Inertia Wheel Mass Wheel Radius
Wagon \(A\) Solid disk \[\frac{1}{2} M R^2\] \[ 0.5 \, \text{kg} \] \[ 0.1 \, \text{m} \]
Wagon \(B\) Solid disk \[\frac{1}{2} M R^2\] \[ 0.2 \, \text{kg} \] \[ 0.1 \, \text{m} \]
Wagon \(C\) Hollow hoop \[M R^2\] \[ 0.1 \, \text{kg} \] \[ 0.1 \, \text{m} \]

Three wagons have identical total mass (including their wheels) and each has four wheels. However, the wheels on each wagon have different designs with varying mass distributions and radii as shown in a reference chart. When accelerating each wagon from a standstill to \( 10 \) \( \text{m/s} \), which wagon requires the most energy input?

Intermediate
Mathematical
MCQ

A small sphere hangs from a string attached to the ceiling of a uniformly accelerating train car. It is observed that the string makes an angle of \(37^\circ\) with respect to the vertical. The magnitude of the acceleration \(a\) of the train car is most nearly:

Beginner
Proportional Analysis
MCQ

A meterstick is supported at its center, which is aligned with the center of a cradle located at position \( x = 0 \) \( \text{m} \). Two identical objects of mass \( 1.0 \) \( \text{kg} \) are suspended from the meterstick. One object hangs \( 0.25 \) \( \text{m} \) to the left of the support point, and the other object hangs \( 0.50 \) \( \text{m} \) to the right of the support point. The system is released from rest and is free to rotate. Which of the following claims correctly describes the subsequent motion of the system containing the meterstick, cradle, and the two objects?

Advanced
Mathematical
GQ

A person is standing at the edge of the water and looking out at the ocean. The height of the person’s eyes above the water is \( h = 1.8 \, \text{m} \), and the radius of the Earth is \( R = 6.38 \times 10^6 \, \text{m} \). How far is it to the horizon (in meters)? In other words, find the distance \( d \) from the person’s eyes to the horizon. Note at the horizon, the angle between the line of sight and the radius of the Earth is \( 90^\circ \).)

Beginner
Conceptual
GQ

Are astronauts really “weightless” while in orbit?

Advanced
Mathematical
FRQ

Priscilla the Penguin stands at the edge of a rock ledge and tosses a small ice cube directly upward with an initial velocity of \( v_0 \). The ice cube’s initial height above the ground is \( 3.25 \, \text{m} \), and it reaches its maximum height above the ground \( 0.586 \, \text{s} \) after being thrown. The ice cube then plummets to the ground, missing the edge of the rock ledge on its way down.

Beginner
Conceptual
MCQ

Two objects, \( A \) and \( B \), move toward one another. Object \( A \) has twice the mass and half the speed of object \( B \). Which of the following describes the forces the objects exert on each other when they collide and provides the best explanation?

Intermediate
Proportional Analysis
MCQ

Four systems are in rotational motion. Which of the following combinations of rotational inertia and angular speed for each of the systems corresponds to the greatest rotational kinetic energy?

System Rotational Inertia Angular Speed
A \( I_0 \) \( \omega_0 \)
B \( I_0 \) \( 4\, \omega_0 \)
C \( 2 I_0 \) \( 2\, \omega_0 \)
D \( 6 I_0 \) \( \omega_0 \)
Intermediate
Conceptual
GQ

You throw a ball straight upward. It leaves your hand at \( 20 \) \( \text{m/s} \) and slows at a steady rate until it stops at the peak. The ball then comes back down, speeding up steadily until it hits the ground with the same speed it left your hand. Draw the velocity vs. time graph or explain it in terms of functions.

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