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?
50 J
1,250 J
2,000 J
5,000 J
Which statement best explains how iron can become a magnet?
Atoms have smaller nuclei.
Electrons are easily removed,
Electrons spin in a unique direction.
Atoms are strongly bonded together.
Two parallel copper wires are each carrying the same electrical current in the same direction. Which statement explains how they respond to each other?
They repel each other, because they have opposite magnetic fields.
They repel each other, because they have similar magnetic fields.
They strengthen each other, because they have opposite magnetic fields.
They strengthen each other, because they have similar magnetic fields.
Which of the following electromagnets would have the greatest magnetic fi eld?
The diagram below shows a bar magnet within a coil of conducting wire. The magnet is moved back and forth. The magnet never has contact with the wire.
As the magnet is moved, the wire will
have an electric current.
decrease in temperature.
become negatively charged.
demagnetize the bar magnet.
The diagram below shows current flow through a wire.
Which of the following represents the magnetic field resulting from the current?
Windmills are used to convert wind energy into a more useful form. In most cases, there are three steps in this process. The energy is in a different form at each step. Which of the following flowcharts shows the most likely order of the energy changes?
wind energy ➡️ mechanical energy ➡️ electrical energy
wind energy ➡️ mechanical energy ➡️ solar energy
wind energy ➡️ solar energy ➡️ electrical energy
wind energy ➡️ electrical energy ➡️ mechanical energy
In the accompanying diagram, a potential difference is induced in a rectangular wire loop as it is rotated at constant speed between two magnetic poles.
If the direction of the field is reversed and the speed of rotation is doubled, the magnitude of the maximum induced voltage will be
four times as great
one-half as great
the same
twice as great
What is the main advantage of using alternating current (AC) over direct current (DC) when transmitting electricity?
AC power lines need less insulation than DC power lines.
AC makes it easier to step voltage up or down with transformers, as compared to DC.
AC has fewer power surge problems than DC
AC is not affected by the use of transformers, but the use of DC requires transformers.
The primary coil of a transformer has 400 turns; the secondary coil has 1,000 turns. An alternating current is sent through the primary coil. The voltage in the primary coil has an amplitude of 17 V. Which statement best describes the voltage amplitude in the secondary coil?
between 17 V and 50 V, because the coils form a step-up transformer
between 0 V and 17 V, because the coils form a step-down transformer
between 0 V and 17 V, because transformer coils are insulators
between 17 V and 50 V, because transformer coils are conductors
The diagram shows a wire loop rotating between magnetic poles. During 360 degrees of rotation from the position shown, the induced voltage changes in