Water can provide energy that may be changed into electricity. Which kind of water could be used to provide electricity?
pure
moving
cold
;deep
Two workers use a ramp to help lift a box onto a dock as shown below. Use the diagram, to answer the following question.
Despite the advantage gained by the ramp there is loss of energy mainly due to
friction between the box and the ramp
the length of the ramp
the rope stretching when pulled
two people pulling the rope
Noah carried a skateboard up a hill and then rode the skateboard down the hill. When Noah reached the bottom of the hill he rolled to a stop. When did Noah have the most potential energy?
while carrying the skateboard up the hill
while standing on the skateboard at the top of the hill
while riding the skateboard down the hill
while standing on the skateboard at the bottom of the hill
The figure below shows a wagon that moves from point X to point Y.
Which of the following best describes the wagon's change in energy as it coasts from point X to point Y?
The wagon has the same kinetic energy at point X and point Y.
The wagon has less kinetic energy at point Y than at point X.
The wagon has the same potential energy at point Y and at point X.
The wagon has less potential energy at point Y than at point X.
A student swings a bat horizontally, making contact with a ball thrown to her. The ball leaves the bat, and the bat continues moving through the rest of the swing.
Which of the following statements best describes the change in energy necessary to do work on the ball?
All the kinetic energy of the bat is converted to work
All of the potential energy of the bat is converted to work.
Some of the kinetic energy of the bat is converted to work.
Some of the potential energy of the bat is converted to work.
A 2.0 kg mass is moving with a speed of 3.0 m/s. What is the kinetic energy of the mass?
1.5 J
6.0 J
9.0 J
18.0 J
Starting from rest a 2 kg block of wood slides a distance of two meters down a frictionless slope, as shown.
What is the approximate kinetic energy of the wooden block at the bottom of the slope
20 J
40 J
200 J
400 J
A man applies a force of 100 N to a rock foe 60 seconds, but the rock does not move. What is the amount of work done on the rock?
0.0 J
6.0 J
100 J
6000 J
A steel ball is dropped from a height (h) of 90 m as shown in the diagram below.
What is the potential energy (PE) and kinetic energy (KE) of the ball at h=36?0 m
PE = 240 J and KE = 240 J
PE = 240 J and KE = 360 J
PE = 360 J and KE = 240 J
PE = 360 J and KE = 360 J
A student exerts a force of 500 N pushing a box 10 m across a floor in 10 seconds. How much work does the student perform?