equilibrium occurs when..
everything is equal
the weight of a person can be represented by a vector that acts..
straight down, even if a person is standing on a hill
the average and instantaneous velocities are always the same when the acceleration is..
0
an object is thrown vertically upward at the Earth's surface. Take the upward direction as positive. the velocity and acceleration at maximum height are..
0,-g
a car is traveling eastward at a speed of 40 m/s when the breaks are applied. what is the direction of the acceleration if the only forces on the car are frictional and there is no wind?
W
the direction of the net force on an object is..
in the same direction as the object's acceleration
when there is no net force on an object, it may be..
moving in a straight line at a constant speed
when you look at the speedometer in a moving car, you see the car's..
instantaneous speed
acceleration is defined as the CHANGE in
velocity divided by the time interval.
a train travels 6 meters in the first second of travel, 6 meters again during the second second of travel, and 6 meters during the third second of travel. Its acceleration is...
0 m/s
a car starts from rest after 7 second it is moving at 42 m/s. what is the cars average acceleration?
6 m/s
In the absence of air resistance, objects fall at constant..
acceleration
a ball is thrown upwards and caught when it comes back down. In the absence of air resistance, the speed of the ball when caught would be..
the same as the speed it had when thrown upwards
Suppose you take a trip that covers 180 km and takes 3 hours to make. Your average speed is..
60 km/h
a ball is thrown straight up. At the top of its path its instantaneous speed is..
0 m/s
how does the acceleration of an object change in relation to its mass? it is..
inversely proportional
When an object reaches terminal velocity its acceleration is
0 m/s squared
suppose the force of friction on a sliding object is 25 N. The force needed to maintain a constant velocity is..
25 N
a book weighs 4 N. when held at rest in your hands, the net force on the book is..
0 N
a girl pills on a 10-kg wagon with a constant force of 20 N, what is the wagon's acceleration?
2 m/s
a force of 3 N accelerates a mass of 3 kg at the rate of 1 m/s. the acceleration of a mass of 6 kg acted upon by a force of 6 N is..
the same
A box is dragged without acceleration in a straight-line path across a level surface by a force of 13 N. What is the frictional force between the box and the surface?
13 N
if the force acting of a car doubles, what happens to the cart's acceleration?
it doubles
a 20-N falling object encounters 4 N of air resistance. The magnitude of the net force on the object is..
16 N
a sportscar has a mass of 1500 kg and accelerates at 5 meters per second squared. what is the magnitude of the force acting on the sportscar?
7500 N
if you lift two loads up one story, how much work do you do compared to lifting just one load up one story?
four times as much
if Nellie Newton pushes an object with twice the force for twice the distance, she does..
four times the work
the unit of work is the..
joule
power is defined as the..
work done on an object divided by the time taken to do the work
the unit of power is the..
watt
a job is done slowly, and an identical job is done quickly. Both jobs require the same amount of work but different amounts of..
power
which requires more work: lifting a 70-kg sack vertically 2 meters, or lifting a 35-kg sack vertically 4 meters?
both require the same amount of work.
an object that has kinetic energy much be..
moving
Ball A has triple the mass and speed of ball B. What is the ration of kinetic energy of ball A to ball B?
27
what is the kinetic energy of a 0.135 kg baseball thrown at 40.0m/s?
108 J
what is the potential energy of a 1 kg mass 1 m above the ground?
9.8 J