Review problems
Chapter 9:
1. A 60.0 gram egg moving at 4.8 m/s
is caught by a student.
A. If the time of interaction
is .25 seconds, what is the average force on the egg ?
B.If the maximum force the egg can
withstand is 650 Newtons, what minimum time is required to keep the egg
intact ?
2. A. What impulse is required to stop a .250
kg baseball traveling at 42.0 m/s ?
B.If the ball is in the
fielder’s mitt for .100 seconds as it is stopped, what is the average force
acting on the ball ?
3. The velocity of a 50.0 gram shell leaving a 3.00 kg rifle is 400.0 m/s. What is the recoil velocity of the rifle ?
4. Spiderman is parked in his Spidermobile (the car and mass of Spiderman and car is 1250 kg). The Evil Hobgoblin sends a huge boulder, mass 3350 kg, toward the car. The boulder hits the car with a velocity of 10 m/s and is slowed down to a velocity of 5 m/s. What speed does the collapsed car with Spiderman in it leave the boulder with ?
5. An angry Spiderman leaves the wreckage of his Spidermobile and runs toward the 90.0 kg Hobgoblin. Hobgoblin runs toward Spiderman with a velocity of – 5.0 m/s while the 80 kg Spiderman runs toward Hobgoblin with a velocity of 8.0 m/s If Spiderman grabs Hobgoblin and hangs onto him after the collision, with what velocity will the two of them travel at after the collision ?
CHAPTER 10:
6. A weight lifter heaves a 200.0 kilgram barbell from the floor to a position directly above his head. If the distance from the floor to his extended arms is 2.50 meters, how much work has the weightlifter done ?
7. How much power does a 63.0 kg athlete develop as he climbs a 5.2 meter rope in 3.5 seconds ?
8. How much work is done in sliding a 45.5 kg wooden trunk across the floor at a constant velocity if the coefficient of friction between the trunk and floor is .250 ?
9.A 23.0 cm screwdriver is being used to pry open a can of paint. If the fulcrum is 2.00 cm from the end of the blade and 84.3 Newtons is exerted on the end of the screwdriver, how much force will act on the paint can if the screwdriver acts as an ideal machine ?
10. A pulley system is 85 % efficient. How much rope must be pulled in if a force of 648 Newtons is needed to lift a 105 kg desk 2.46 meters ?
11. A ramp is 5 meters high and is 12 meters along the surface of the ramp. If a box that has a mass of 150 kg needs a force of 700 Newtons of force to push it up the ramp, what is the efficiency of the ramp ?
CHAPTER 9:
1. A. -1.15 Newtons
B. .049 seconds
2. A. 10.5 kg m/s
B. 105 Newtons
3. -6.67 m/s
4. 13.4 m/s
5. 1.12 m/s
Chapter 10:
6. 4900 Joules
7. 917 Watts
8. 1110 Joules
9. 885 Newtons
10. 4.6 meters
11. 87.5 %