Physics 201 MWF10:20 Fall 2004

Exam I Chapts. 1-4 in Cutnell and Johnson 6th ed.


Show all your work. Partial credit will be given if earned. Write your answers in the blanks provided.


(18 pts) 1. A box is suspended from the lower end of a vertical rope. You apply an upward force of 36.0 N to the upper end of the rope. Starting from rest, the box travels downward a distance of 6.0 m in 2.0 s. The rope has negligible weight. What is the weight of the box?



Ans. _____________________


(22 pts) 2. A small rock is projected from the roof of a tall building. The initial velocity of the rock has magnitude 20.0 m/s and a direction of 53.0° above the horizontal. The rock strikes the ground 4.5 s after being thrown.



a) What is the height h of the building?

Ans. _________________

b) What are the horizontal and vertical components of the velocity of the rock just before it strikes the ground?

Ans. horizontal _____________

vertical ______________


(18 pts) 3. A speeding truck passes a police car that is initially at rest. The truck travels south along the straight road with a constant speed of 30.0 m/s. At the instant that the truck is alongside the car, the car starts to accelerate southward with a = 2.5 m/s².

a) What distance does the police car travel before it overtakes the truck?

Ans. _____________________

b) What is the speed of the police car when it overtakes the truck? (Note: the car is capable of high speeds).

Ans. ______________


(22pts) 4. A window washer applies a force F  to a scrub brush to push it up a vertical wall. The force F  has magnitude 80.0 N and is directed at 53.0° above the horizontal, as shown in the sketch. The scrub brush has mass 3.0 kg and the coefficient of kinetic friction between the brush and the wall is 0.30.


a) What is the magnitude of the normal force that the wall exerts on the brush?
Ans. __________________

b) What is the magnitude of the acceleration of the brush?

Ans. _________________


(18 pts) 5. Two soccer players are running as one passes the ball to the other. Mia is running relative to the ground at 3.0 m/s in a direction of 30.0° east of south. The ball is traveling at 4.5 m/s due east, relative to the ground. What is the speed of the ball relative to Mia?

Ans. ________________