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Advanced
Mathematical
GQ

A pendulum consists of a mass \( M \) hanging at the bottom end of a massless rod of length \( \ell \) which has a frictionless pivot at its top end. A mass \( m \), moving with velocity \( v \), impacts \( M \) and becomes embedded. In terms of the given variables and constants, what is the smallest value of \( v \) sufficient to cause the pendulum (with embedded mass \( m \)) to swing clear over the top of its arc?

Beginner
Conceptual
MCQ

A westward–moving car is changing its speed. The net force on the car ____.

Intermediate
Mathematical
GQ

A coffee cup on the dashboard of a car slides forward when the driver decelerates from \(45 ~ \frac{\text{km}}{\text{hr}}\) to rest in \(3.5 \, \text{s}\) or less. What is the coefficient of static friction between the cup and the dash? Assume the road and the dashboard are completely horizontal.

Intermediate
Mathematical
MCQ

What is the net torque acting on the pivot supporting a \(10 \, \text{kilogram}\) beam \(2 \, \text{meters}\) long as shown above? Assume that the positive direction is clockwise.

Intermediate
Mathematical
FRQ

A \(1509 \, \text{g}\) wood block is being pulled by the force meter at a constant velocity. Using the graph above, find:

Intermediate
Mathematical
FRQ

While Santa was delivering presents to the children of Nashville, Tennessee he experienced a strong wind perpendicular to his motion.

Advanced
Mathematical
GQ

A \(2 \, \text{kg}\) model rocket is launched with a thrust force of \(275 \, \text{N}\) and reaches a height of \(90 \, \text{m}\), at which point the thrust cuts out, but the rocket continues moving at \(150 \, \text{m/s}\). What is the average air resistance force acting on the rocket during its ascent?

Intermediate
Conceptual
MCQ

Three identical blocks are being pulled or pushed across a rough horizontal surface by force of identical magnitude F, as shown in the drawing below. Rank the kinetic frictional forces that act on the blocks from smallest to greatest.

Intermediate
Mathematical
GQ

A car moves at constant speed in a circle of radius 75 m on a horizontal road. The coefficient of static friction is 0.62. Find the maximum speed the car can go without sliding.

Intermediate
Mathematical
FRQ

You throw a rock straight up with an initial velocity of \( 5.0 \, \text{m/s} \).

Beginner
Mathematical
GQ

Police officers have measured the length of a car’s tire skid marks to be \( 23 \, \text{m} \). This particular car is known to decelerate at a constant \( 7.5 \, \text{m/s}^2 \). What was the car’s initial velocity?

Intermediate
Proportional Analysis
MCQ

A uniform copper disk of radius \( R \) has a moment of inertia \( I \) around an axis passing through the center of the disk perpendicular to its plane. If the radius of the disk were only \( \dfrac{R}{2} \), but the thickness were the same, what would be the moment of inertia in terms of \( I \)? Hint: The moment of inertia of a solid disk about its center is \(\frac{1}{2} M R^{2}\).

Intermediate
Conceptual
MCQ

Why do raindrops fall with constant speed during the later stages of their descent?

Intermediate
Conceptual
MCQ

Given the graph of velocity versus time for a duck flying due south for the winter, at what labeled point did the duck stop its forward motion?

Intermediate
Mathematical
FRQ

A satellite circling Earth completes each orbit in \(132 \, \text{minutes}\).

Advanced
Mathematical
FRQ

The system in the Figure is in equilibrium. A concrete block of mass \(225 \, \text{kg}\) hangs from the end of a uniform strut whose mass is \(45.0 \, \text{kg}\).

Beginner
Mathematical
MCQ

An object weighing 120 N is set on a rigid beam of negligible mass at a distance of 3 m from a pivot, as shown above. A vertical force is to be applied to the other end of the beam a distance of 4 m from the pivot to keep the beam at rest and horizontal. What is the magnitude F of the force required?

Advanced
Conceptual
GQ

A man with mass \( m \) is standing on a rotating platform in a science museum. The platform can be approximated as a uniform disk of radius \( R \) that rotates without friction at a constant angular velocity \( \omega \). Two students are discussing what the man should do if he wishes to change the angular velocity of the platform.

Student A says that the man should run towards the center of the platform, because this will decrease the moment of inertia of the man-platform system. Since \( L \propto I \), the angular momentum will decrease proportionately and the platform will slow down.

Student B says that since the platform is rotating counterclockwise, the man should run in a clockwise direction to slow the platform down. His feet will exert a frictional torque on the platform, which will cause an angular acceleration of the man-platform system.

Explain what is correct and incorrect about each students statement if anything.

Intermediate
Conceptual
MCQ

Which of the following graphs represent an object having zero acceleration?

Advanced
Mathematical
FRQ

The angular velocity of an electric motor is \(\omega = \left(20 – \frac{1}{2} t^2 \right) \, \text{rad/s}\), where \(t\) is in seconds.

Intermediate
Mathematical
GQ

Rex, an auto mechanic, is raising a \( 1200 \) \( \text{kg} \) car on his hydraulic lift so that he can work underneath. If the area of the input piston is \( 12.0 \) \( \text{cm}^2 \), while the output piston has an area of \( 700 \) \( \text{cm}^2 \), what force must be exerted on the input piston to lift the car?

Advanced
Conceptual
MCQ

A solid sphere of mass \( M \) and radius \( R \) rolls without slipping down an inclined plane starting from rest. Select all that would affect the angular velocity of the sphere at the bottom of the incline.

Advanced
Proportional Analysis
MCQ

A centripetal force of \( 5.0 \) newtons is applied to a rubber stopper 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 stopper?

Advanced
Mathematical
GQ

Find the downward acceleration of an elevator, given that the ratio of a person’s stationary weight to their weight in the elevator is \(5:4\).

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