concept of physics ch.1-6 midterm

the weight of a 6kg of salami is about how much in newtons?

60 N

If you exert 450 J in 50 s, your power output is

9W

compared with the mass of a certain object on the moon the mass of the same object on the earth is

the same

the attraction of a persons body towrd earth is called weight. the other way of describing this force is

the pulling of a persons body towards earth

suppose a gun were made of very heavy material suppose also that the pellet has almost no mass. for such a weapon

the recoil force would be lessened

as an object freely falls its

velocity increases

a hockey puck is set in motion across a frozen pond. if ice friction and air resistance are included the force required to keep the puck sliding at a constant velocity is

very small

a liter is a measure of an object's

volume

When a rifle is fired, it recoils so both the bullet and rifle are set in motion. The rifle and bullet ideally acquire

-equal but opposite amounts of -momentum. - kinetic -energy. -velocity

a 1-kg chunk of putty moving at a 5 m/s collides and sticks to a 5kg bowling ball initially at negative 1 m/s the bowling ball and putty have a momentum of

0kgm/s

an object travels 4m in the 1st second of travel 4m again during the 2nd second of travel and 4m again during the 3rd second. its acceleration is therefore

0m/s^2

The power expended when a 100 N barbell is raised 2.0 m in 2 s is

100 W

A car has a mass of 1000 kg and accelerates at 1 m/s2. What is the magnitude of the force exerted on the car?

1000

a car ttraveling at 22 m/s comes to an abrupt halt in 0.2s when it hits a tree. what is the deceleration in meter per second suqared of the car

110

if a car increases its velocity from zero to 60 km/h in 5 s ts acceleration is

12 km/hs

if a rocket initially at rest accelerates at a rate of 25m/s^2 for 1 min its speed will be

1500m/s

A 30-kg girl and a 60-kg boy face each other on friction-free roller blades. The girl pushes the boy, who moves away at a speed of 1.0 m/s. The girl's speed is

2.0 m/s

twenty seconds after starting from rest, a freely falling object on earth will have a speed of about

200 m/s

a pot falls from a ledge and hits the ground two seconds later. the speed with which it hits the ground is about

20m/s

the average speed of a horse that galops a distance of 10 km in a time of 20min is

30 km/h

a 10 N falling object encounters 6N of air resistance. the magnitude of the net force on the objectis

4 N

A rifle of mass 1 kg is suspended by strings. The rifle fires a bullet of mass 1/100 kg at a speed of 400 m/s. The recoil velocity of the rifle is about

4 m/s

a ball is moving at 12,m/s and has a momentum of 48 kg m/s what is the balls mass?

4kg

starting from rest the distance a freely falling object will fall in 10s is about

500 m

a muzzle of velocity of a certain gun is 100m/s. negleting air resistance at the end of the 1 s a bullet fired straight up into the air will have traveled a distance of about

95 m

which has the least mass

a king-size pillow

a rock thrown straihgt upward gets to the exact top if its path.a second later its velocity is

about 10.m/s and its acceleration is about 10m/s^2

a package falls off a truck that is moving at 40 m/s. neglecting air resistance, the horizontal speed of the package just before it hits the ground is

about 40 m/s

disregarding air resistance, objects fall at a constant

acceleration

a force is a pair because it has both

action and reaction counterparts

when you stand at rest on a pair of bathroom scales the reading on the scales will always

add to your weight

padded dashboards in cars are safer in an accident than non-padded ones because an occupant hitting the dash has

both increased time of impact and deccreased impact force

before a falling object has reached it terminal velocity its acceleration is

constant

whirl a rock at the end of a string and it follows a circular path. if the string breaks, the tendency of the rock is not to

continue to follow a circular path

if an object's mass is increasing while a constant force is applied to the object, the acceleration

decreases

your weight is

dependent on your mass

the two measurements necessary for calculating velocity are

distance and time

in each second of fall the distance a free falling object will fall is

icreasing

A feather and a coin dropped in a vacuum fall with equal

impact times. impact speeds. accelerations

Compared with the force that brings a small car to a stop, the force required to bring a heavy truck to a stop in the same time

is less

whenever the net force on an object is zero, it acceleration

is zero

a light object is dropped a second earlier, than a heavier object is dropped. the heavier object reaches the ground 10 m below

later than the light object

Which requires more work: lifting a 50-kg sack vertically 2 m or lifting a 25-kg sack vertically 5 m?

lifting the 25 kg sack

aristole relied on----in explaining nature

logic

when you are in the way of a fast - moving object and can't get out of its way yoou will suffer a lessor force of impact if you decrease its momentum over a

long time

the mack truck and a volkswagen traveling at the same speed have a head on collision the vehicle to undergo the least change will be the

mack truck

denity is the ratio of

mass to volume

An object that has kinetic energy must be

moving

the scientist to first introduce the concept of mathematical models was

newton

the conservation of momentum is not related to

newtons fourth law

a freight train rolls along a track with considerable momentum. if it has three times as much mass, and three times as much speed its momentum is

nine times as much

a rocket accelerated as it travels because

of its applied thrust

When a car rolls to a stop at the top of a hill, its kinetic energy is transformed to

potential energy

A job is done slowly, while an identical job is done quickly. The job done quickly, requires more ____

power

a sheet of paper can be withdrawn from under a container of milk without toppling it if the paper is jerked quickly. because of its inertia

the milk carton has no acceleration

a ball is thrown vertically into the air. neglecting air resistance its time coming down compared to its time going up is

the same

a ball is thrown vertically into the air. neglecting air resistance, its speed when it returns to its starting level compared to its initial speed is

the same

The force required to support an object in a gravitational field, is equal to

the weight of the object

Which has lgreater kinetic energy, a car traveling at 30 km/h or a car of half that mass traveling at 60 km/h?

the 60km/h car