Physics 1408

Since you may take the online quizzes as often as you like, your highest average should be pretty good. However, in order to keep track, you must fill out the student name and id# part of the form.

Question 1. A 50 kg crate rests on a horizontal floor. If a force of 150 N to the right is exerted on the crate but it doesn't move, then the force of friction (in N) is

(a) 0     (b) 500 left     (c) 500 right     (d) 150 right     (e) 150 left

 

 

Question 2. The force on the crate from the previous question is increased to 250 N to the right so that the crate moves with constant velocity. The net force (in N) on the crate is

(a) 0     (b) 500 left     (c) 500 right     (d) 250 right     (e) 250 left

 

 

Question 3. A 0.11 kg hockey puck is brought to rest after sliding across the ice for 15 m. If its initial speed is 6 m/s, then the coefficient of sliding friction is

(a) 0     (b) 0.01     (c) 0.12     (d) 0.24     (e) 0.5

 

 

Question 4. If we do not ignore air resistance, then as a 600 N skydiver falls faster and faster through the air, her acceleration

(a) increases     (b) decreases     (c) remains the same    

 

 

Question 5. At terminal velocity the force of gravity (in N) on our skydiver from question 4 will be

(a) 0     (b) 300 up     (c) 300 down     (d) 600 up     (e) 600 down

 

 

Question 6. At terminal velocity the force of air resistance (in N) on the skydiver from question 4 will be

(a) 0     (b) 300 up     (c) 300 down     (d) 600 up     (e) 600 down

 

 

Question 7. At terminal velocity a spring scale hooked between the skydiver's support harness and the parachute rigging would show a weight (in N) of

(a) 0     (b) 300     (c) 600     (d) 900     (e) 1200

 

 

Question 8. If we could "turn off" air resistance completely, then the spring scale from question 7 would show that the skydiver's weight (in N) would be

(a) 0     (b) 300     (c) 600     (d) 900     (e) 1200

 

 

Question 9. With what maximum speed (in m/s) can a car round a flat curve of radius 64 m without sliding if the coefficient of static friction between the tires and the road is 0.4?

(a) 0     (b) 4     (c) 16     (d) 32     (e) 48

 

 

Question 10. Tarzan (mass m = 90 kg) swings across a river on a 10-m long (massless) vine. If Tarzan's speed at the bottom of his swing is 8 m/s, then the maximum tension (in N) in the vine will be

(a) 1476     (b) 2311     (c) 3517     (d) 4783     (e) 5192

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