AP Physics Unit 3

A rod on a horizontal tabletop is pivoted at one end and is free to rotate without friction about a vertical axis, as shown in the diagram.  A force F is applied at an angle θ to the rod.  If F were to be applied perpendicular to the rod, at what distance from the axis should it be applied in order to produce the same amount of torque?

A ball is suspended by a lightweight string, as shown in the figure.   The ball is displaced to position 1 and released. The four labelled positions are evenly spaced along the arc of the ball's motion.  
Between which adjacent pairs is the gain in kinetic energy the greatest?

A solid metal ball and a hollow plastic ball of the same external radius are released from rest in a large vacuum chamber.  When each has fallen 1m, they both have the same

A student weighing 700 N climbs at a constant speed to the top of an 8m verticle rope in 10 s.  The average power expended by the student to overcome gravity is most nearly

Three forces act on an object.  If the object is in translational equilibrium, which of the following must be true:
i. The vector sum of the three forces must equal zero.
ii. The magnitude of the three forces must be equal.
iii. All three forces must be parallel.

The electrical resistance between X and Y is

The figure above shows two particles, each with a charge of Q+, that are located at the opposite corners of a square with a side d.
What is the direction of the net electric field at point P.

A child pushes horizontally on a box of mass m which moves with constant speed v across a horizontal floor. The coefficient of friction between the box and floor is μ. At what rate does a child do work on the box?

The maximum speed of the electrons emitted by a metal surface when it is illuminated by light depends on which of the following?

An open cart on a level surface is rolling without frictional loss through a verticle downpour of rain, as shown in the figure. As the cart rolls, an appreciable amount of the rainwater accumulates in the cart. The speed of the cart will