G Syllabi > 05 Work and Energy > G Energy Mock Test
1. A 347 W winch lifts a 790. kg load.
A. What is the force needed to lift the load? (7740 N)
B. What time will it take to lift the load 3.40 m? (75.9 s)
C. If the winch is 82% efficient, what must be the power input in Watts? (e = output/input) (423 Watts)
2. A rollercoaster starts 512 kg cars at an elevation of 11.0 m and a speed of 7.50 m/s.
A. What is the total energy of the car? (69,600 J)
B. What is the car’s speed when it is at an elevation of 7.80 m? (10.9 m/s)
C. The cars are stopped at an elevation of 4.50 m with a force of 5600 N in what distance? (8.40 m)
3. Random Energy Questions:
A. What time will it take a 34.0 W heater to evolve 1250 J of Heat? How much heat would it put out in 1.8 minutes? (36.8 s, 3670 J)
B. A 1260 kg car going 6.7 m/s on the top of an 8.0 m tall hill is brought to rest at the bottom by a force of 34,500 N in what distance? (3.68 m)
C. A 62.0 kg cart is going 6.17 m/s at the bottom of a hill. A force of 272 N acts for a distance of 5.80 m to speed it up. What is the height of the hill if the cars are going 3.78 m/s after this at the top of the hill? (3.81 m)
4. Red Elk drives a tractor that has a 47 HP engine. (1 HP= 745.7 W) It is dragging an 8700 kg sled along the ground where the coefficient of friction is .72.
A. What force must the tractor exert to slide the sled at a constant speed? (61,400 N)
B. How far can it drag in the sled in 3.00 minutes? (103 m)
C. A baseball pop fly (mass .145 kg) goes straight up, and is observed at a height of 9.0 m above the bat to be going 16 m/s up by a radar gun. (By someone in a helicopter) What was the velocity of the ball when it left the bat? (h=0) (20.8 m/s)