# Physics 152 practice exam

Part I. Multiple Choice Questions [2 pts each]

Directions: Choose the alternative that best completes the statement or answers the question. Unless otherwise stated, assume ideal conditions (no air resistance, uniform gravity, etc.)

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1) Let A = !3i + 4 ˆ and B = i + 2 ˆ . What is A • B ?

j

j

(A) 3

(B) 5

(C) 8

(D) None of these.

2) A particle moving along the x axis has a potential energy given by the function U(y) = -5x4, where x is in meters and U is in joules. What is the x-component of the force acting on the particle at x = 2 m? (A) -160 N

(B) -80 N

(C) 160 N

(D) None of these.

3) A railroad tank car contains milk and rolls at constant speed along a straight level track. The milk begins to leak out the bottom. The car’s forward momentum then .

(A) increases.

(B) decreases.

(C) remains the same.

(D) Not enough information.

4) A bowling ball strikes an upright bowling pin. The bowling ball has three times the mass of the pin. Which experiences the greater change in speed as a result of the collision? (A) Ball.

(B) Pin.

(C) Same change in speed.

(D) Not enough information.

5) A satellite is in a circular orbit of radius r about the Earth. Let the magnitude of the force of gravity acting on the satellite due to the Earth equal F. What is the correct expression for the work done by gravity on the satellite?

(A) 0

(B) F(2πr)

(C) F(πr2)

(D) None of these.

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PRACTICE EXAM 2B – PHYS 15200

Part II. Word Problems [30 pts each]

Directions: Solve each problem. Do not write on the formula sheet. Show your work to receive full credit. Box your final answer and record its appropriate unit. Unless otherwise stated, assume ideal conditions (no air resistance, uniform gravity, etc.)

PROBLEM 1

A rocket (mass 3M) traveling east at 100 m/s suddenly explodes into two pieces. Piece 1 (mass M)...

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