2019 #1 Free Response Question - AP Physics 1 - Exam Solution

The video tutorial covers a problem from the 2019 AP Physics exam involving two blocks on a frictionless surface, with a focus on graphing the speed of the center of mass. The initial solution incorrectly graphs the speed of block one, leading to a correction. The tutorial also explores angular momentum changes in a sphere pushed by a plunger, emphasizing the role of net torque.

What is the main characteristic of the surface between points C and D?

• It is completely frictionless.

• It has a rough surface.

• It is inclined.

• It is sticky.

What happens to Block 1 when it reaches point B?

• It reverses direction.

• It accelerates further.

• It stops moving.

• It loses contact with the plunger.

How does the speed of Block 1 change from point C to D?

• It increases.

• It remains constant.

• It decreases due to friction.

• It becomes zero.

What is the correct graph representation for the speed of the center of mass of the two-block system?

• A vertical line at point E.

• A horizontal line from D to F.

• A constant positive slope throughout.

• A constant negative slope throughout.

What is the main focus of Part B in the problem?

• The collision of two blocks.

• The angular momentum of a sphere.

• The friction between blocks.

• The acceleration of Block 1.

Which force causes a torque on the sphere from C to D?

• Normal force

• Gravitational force

• Frictional force

• Applied force by the plunger

During which interval does the sphere experience a change in angular momentum?

• B to C

• A to B

• D to E

• C to D

What is the condition for angular momentum to be conserved?

• Acceleration is constant.

• Velocity is constant.

• Net torque is zero.

• Net force is zero.

What is the effect of the plunger's force on the sphere's angular momentum?

• It reverses angular momentum.

• It causes no change in angular momentum.

• It decreases angular momentum.

• It increases angular momentum.

What is the main takeaway regarding the explanation for Part B?

• No explanation is required.

• Explanations should be avoided.

• Only brief explanations are needed.

• Detailed explanations are necessary.