# physics exam 1

### 86 terms by greenm2

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mass

### objects that have zero acceleration

objects moving at constant velocity, at rest, and in mechanical equilibrium

### the two measurements necessary for calculating average speed

distance and time

### if a freely falling object were somehow equipped with an odometer to measure the distance it travels, then the amount of distance it travels each succeeding second would be

greater than the second before

mass

### a force is a vector quantity because it has both

magnitude and direction

zero

### a player hits a ball with a bat. the action force is the impact of the bat against the ball. the action to this force is the

force of the ball against the bat

### which of the following has the largest momentum relative to earth

the pickup truck speeding along the highway

### if you push an object just as far while applying twice the force, you do

twice as much work

momentum

### newton discovered

that gravity is universal

always false

decreases

atmosphere

### water pressure is greatest against

all sides of a submerged object

### the impulse-momentum relationship and example

impulse is equal to the change in momentum. when a golfer is about to hit the ball, zero force is exerted until contact. when contact arrives, there is an increase in momentum due to the impulse

### newton's first law of motion

every object continues in a state of rest or of uniform speed in a straight line unless acted upon by a nonzero force. inertia

### newton's second law of motion

the acceleration produced by net force is directly proportional to the net force, is in the same direction as the net force, and is inversely proportional to the mass of the object. force of hand accelerates brick

### newton's third law of motion

whenever one object exerts a force on a second object, the second object exerts an equal and opposite force on the first. earth pulls on ball and ball pulls on earth

### difference between velocity and acceleration

velocity is speed and direction of the object and acceleration is moving things that undergo variations in motion

### the scientist to first introduce the concept of inertia

galileo

the gravitational attraction between you and the earth

5 N

### the two measurements necessary for calculating average speed are

distance and time

### if a nonrotating object has no acceleration, then we can say for certain that it is

in mechanical equilibrium

double

60 m/s

### an archer shoots an arrow. consider the action force to be the bowstring against the arrow. the reaction to this force is the

arrow's push against the bowstring

doubled

### the difference between impulse and impact force involves the

time the force acts

### a cannon recoils from firing a cannonball. the speed of the cannon's recoil is small because the

cannon has more mass than the ball

on the wall

momentum

### if you do work on an object in half the time, your power output is

twice the usual power output

### newton discovered

that gravity is universal

### a rock is thrown upward at 50 degrees with respect to the horizontal. as it rises, its horizontal component of velocity

remains unchanged

unchanged

### galileo's concept of inertia

the name given to the property by which objects resist which objects resist changes in motion is friction

### two quantities necessary for a vector quantity

magnitude and direction

### support force is called normal force because

the force acts at right angles to the surface

### the direction of friction compares with the velocity of a sliding object because

when you push hard enough on sliding furniture to match the friction, the net force is zero and it slides at constant velocity

### is velocity is a vector? is speed?

velocity is a vector and speed is not because constant velocity means constant speed and constant direction. constant speed merely means steady speed. vector quantities specify direction and magnitudes and velocity does this, not speed

### speed=

distance covered/travel time

### acceleration=

change of velocity/time of interval

### mass

quantity of matter in an object

### weight

the force upon an object due to gravity

### EF=0

equilibrium rule. E "the vector sum of." F stands for forces. vector quantities are equal to zero

### inertia

the property by which objects resist changes in motion

mass X velocity

### momentum=

mass X speed when direction is not important

### impulse=

change in momentum

### law of conservation of momentum

in the absence of an external force, the momentum of a system remains unchanged

### elastic collision

when a ball moves and hits another ball and then it stops while the other ball begins to move

### inelastic collision

the objects stick together

force X distance

### energy

the property of a system that enables it to do work

### potential energy

the energy that is stored and held in readiness

weight X height

### kinetic energy

depends on the mass on the object as well as its speed

### kinetic energy=

1/2 mass X speed2

### work energy theorem

work=change in kinetic energy

### law of conservation of energy

energy cannot be created or destroyed; it may be transformed from one form into another, but the total amount of energy never changes

### power=

work done/time interval

### efficiency=

useful energy output/total energy input

force~ m1m2/d2

f=g m1m2/d2

### inverse square law

intensity of an effect from a localized source spreads uniformly throughout the surrounding space and weakens with the inverse square of the distance

### inverse square law

intensity=1/distance2

### projectile

any object that is projected and continues in motion by its own inertia

mass/volume

### density

measure of compactness

weight/volume

force/area

upward force

### liquid pressure=

weight density X depth

### archimedes' principle

an immersed body is buoyed up by a force equal to the weight of the fluid it displaces

### principle of flotation

a floating object displaces a weight of fluid equal to its own weight

p1v1=p2v2

weight of air

### barometer

instrument used to measure the pressure of the atmosphere

### pascal's principle

a change in pressure at any point in an enclosed fluid at rest is transmitted undiminished to all points in the fluid

### bernoulli's principle

where the speed of a fluid increases, internal pressure in the fluid decreases

Example: