Work and Power
DOUBLE JEOPARDY!!
How much work is done in holding a 15 N sack of potatoes while waiting in line at the grocery store for 3 minutes.
0 Joules - no displacement by the force holding potatoes
Calculate the kinetic energy of a car which has a mass of 1000 kg and is moving at the rate of 20 m/s.
200, 000 J
A 10-kg mass is lifted to a height of 2-m. What is its potential energy at this position?
196 J
What does the area under a spring force vs. spring elongation graph represent?
The work done on or by the spring
If 360 Joules of work are needed to lift a crate a distance of 4 meters, what is the weight of the crate?
90 N
What is the velocity of a 500-kg elevator that has 4000-J of kinetic energy?
4 m/s
A 5-kg cat climbing at the top of the tree has a potential energy of 575-J. Find the height of the tree? Round to the nearest whole number.
12 m
A compressed spring in a toy is used to launch a 5-g ball. If the ball leaves the toy with an initial horizontal speed of 5 meters per second, find the minimum amount of potential energy stored in the compressed spring. Do not round answer.
.0625 J
How much time is needed to produce 720 Joules of work if 90 watts of power is used?
8 seconds
DOUBLE JEOPARDY
A tennis ball has 300-J of kinetic energy. If the tennis ball's velocity were to quadruple, how much kinetic energy would the tennis ball have now?
4800 J
A 0.050 kg mass is hanging from a spring whose unstretched length is 10 cm and whose spring constant is 2.5 N/m. What is the final length of the spring after the mass is hung? Do not round answer.
0.296 m
A set of pulleys lifts an 80 kg crate 5 meters in 7 seconds. What power was used?
560 Watts or Nm/s or J/s
A 7-kg bowling ball moves at 3-m/s.How fast must a 2.5-g ping pong ball move to have the same kinetic energy as the bowling ball? Round to the nearest whole number.
159-m/s
An astronaut with a mass of 110.0 kg visits the moon The astronaut climbs 5.0 m up the ladder into his spacecraft and gains 880 J of gravitational potential energy. What is the gravitational field strength on the moon?
1.6 m/s/s
A vertical spring 0.100 meter long is elongated to a length of 0.119 meter when a 1.00-kilogram mass is attached to the bottom of the spring. Find the spring constant of this spring. Round to the nearest whole number
516 N/m
A 25-g paper cup falls from rest off the edge of a tabletop 0.90 above the floor. If the cup has 0.2 J of kinetic energy when it hits the floor, what is the total amount of energy converted to internal energy during the cup's fall? Do not round answer.
0.0205 J