Conceptual Physics Energy
If no external force are acting on a moving object it will...
continue moving at the same velocity
An object in mechanical equilibrium is an object in...
has no acceleration, is at rest, or moving with constant velocity
When an automobile is braked to a stop it's KE is transformed to
heat
If one object has twice as much mass as another object is also has twice as much...
inertia
Your weight
is due to gravitational attraction force between you and the Earth
For an action force, there must be a reaction force that
is exactly equal in magnitude
A kilogram is a measure of an object's....
mass
If the speed of a moving object doubles which of the following also doubles?
momentum
An object that has kinetic energy must be
moving
An object at rest may also have...
potential energy
If you do work on an object in one third the usual time, your power output is
three times as much
An object is propelled along a straight line path by a force. If the net force were doubled the objects acceleration would be....
twice as much
If an object is raised twice as high it's potential energy is
twice as much
If you push an object twice as far while applying the same force you do...
twice as much work
A moving object has
velocity, speed, momentum, and energy
A car maintains a constant velocity of 100 km/hr for 10 s. During this time interval it's acceleration is...
zero
A skydiver who weighs 500 N reaches terminal velocity at 90 km/h. The air resistance on the diver is then
500 N
If a car increases its velocity from zero to 60 km/hr in 10 s, its acceleration is...
6 km/hr
A 5000 kg freight car runs into a 10,000 kg freight car at rest. They couple upon collision and move with a speed of 2 m/s. What was the initial speed of the 5000 kg car?
6 m/s
A 4 kg ball has a momentum of 12 kg m/s. What is the balls speed?
8 m/s
A machine puts out 100 W of power for every 1000 W put into it. The efficiency of the machine is
10%
An object falls freely from rest on a planet where the acceleration due to gravity is 20 meters per second squared. After 5 s the object will have a speed of...
100 m/s
Two identical objects in outer space have a head on collision and stick together. If before the collision one had been moving at 2 m/s and the other at 1 m/s their combined speed after would be..
.5 m/s
The power output required to exert 1 N force over a distance of 1 m in 1 s is
1 W
The force of friction on a sliding object is 10 N. The applied force needed to maintain a constant velocity is...
10 N
A car moving at 50 km/hr skids 20 m with locked brakes. How far will the car skid with locked brakes if it were traveling at 150 km/hr?
180 m
Do 100 J of work in 50 s, and your power output is
2 W
A 2 kg mass has 40 J of PE with respect to the ground. Approximately how high is it above the ground?
2 m
A 1000 kg car moving at 10 m/s brakes to a stop in 5 s. The average braking force is
2000 N
A car has a mass of 1000 kg and accelerates at 2 meters per second. What is the magnitude of the net force on the car?
2000 N
A man weighing 800 N stands at rest on two bathroom scales so that his weight is distributed evenly over both scales. The reading on each scale is...
400 N
An object is pulled northward by a force of 10 N and at the same time another force of 15 N pulls it southward. The magnitude of the resultant force on the object is....
5 N
Using 1000 J of work a toy elevator is raised from the ground floor to the second floor in 20 seconds. The power needed to do this job was
50 W
The impulse momentum relationship is a direct result of
Newton's Second Law
A skydiver jumps from a high flying plane. As her velocity increases her acceleration....
decreases
The two measurements necessary for calculating average speed are....
distance and time
Whereas impulse involves the time that a force acts, work involved the
distance that a force acts
A freight train rolls along a track with considerable momentum. If it rolls at the same speed but has twice as much mass, it's momentum is....
doubled
