Vectors and Motion in Two Dimensions AP Physics 1 FRQ

Vectors and Motion in Two Dimensions AP Physics 1 FRQ – Exam Style Questions etc.

Vectors and Motion in Two Dimensions AP Physics 1 FRQ

Unit: 1. Kinematics

Weightage : 10-15%

AP Physics 1 Exam Style Questions – All Topics

Question

A ball is thrown into the air with an initial velocity of 10 m/s at an angle of 45 degrees above the horizontal, as represented above. Which of the following representations of the velocity and acceleration of the ball is true?

Answer/Explanation

Ans:C

The vertical component of the velocity at its highest point is zero. Since the horizontal component never changes, the speed at the top is at a minimum value.

Question

A ball given an initial velocity of \(v_0\) at an angle θ above the horizontal. The ball travels up and returns to the same height from which it was released. Possible representations of the motion of the ball are shown below.

Which combination of representations correctly represents the vertical component of the ball’s motion?

A I and IV

B II and V

C II and VI

D III and V

E III and VI

Answer/Explanation

Ans:B

The dots represent the position of the object at different points in time. As the ball goes upward, the ball slows down, and as the ball comes downward, it speeds back up, so the dots should get closer together and then further apart. For the graphs, the acceleration of the object is due to gravity the entire time, so it is constant during the entire motion. The slope of velocity-time is the acceleration, so the velocity-time graph should be a straight line.

Question

A train is traveling at a constant speed eastward, and the velocity vector \(v_T\) is shown in the diagram above. The velocity vector \(v_C\) of a cyclist moving at a direction of 15.0° east of north is also shown. Which of the following vectors could represent the velocity of the cyclist as seen by someone on the train?

Answer/Explanation

Ans:B

To determine the velocity of the cyclist as seen by someone on the train, the velocity vector of the train must be subtracted from the velocity vector of the cyclist. This is done using vector addition and reversing the direction of the train vector. So, this would be the cyclist vector plus a vector to the left, so the new velocity vector must be up and to the left.

Question

A ball is thrown and follows a parabolic path, as shown above. Air friction is negligible. Point Q is the highest point on the path. Which of the following best indicates the direction of the acceleration, if any, of the ball at point Q?

Answer/Explanation

Ans:C

Question

The following questions are related to this scenario:

The following pairs of equations show how the x- and y-coordinates of a particle vary with time t. In the equations, A, B, and ω

are nonzero constants. Choose the pair of equations that best answers each of the following questions. A choice may be used once, more than once, or not at all.

Which pair of equations can describe the path of a particle moving with an acceleration that is perpendicular to the velocity of the particle at t = 0 and remains constant in magnitude and direction?
A \(x=Acosωt\) , \(y=Asinωt\)

B \(x=Acosωt\) , \(y=2Acosωt\)

C \(x=At\) , y=\(Bt\)

D \(x=At^2\) , \(y=Bt^2\)

E \(x=At\) , \(y=Bt^2\)

Answer/Explanation

Ans:E

Vectors and Motion in Two Dimensions AP Physics 1 FRQ