Physics

A ball is thrown upward and caught when it comes back down. Neglecting air resistance, the speed with which it is caught is

...the same as the speed it had when thrown upward.

A 10-N falling object encounters 10 N of air resistance. The net force on the object is

0

A falling skydiver of mass 100 kg experiences 500-N air resistance. The acceleration of the skydiver is

0.5 g

If you exert 1 N for a distance of 1 m in 1 s, you will deliver a power of

1 W

A 1-kg glider and a 2-kg glider both slide toward each other at 1 m/s on an air track. They collide and stick. The combined mass moves at

1/3 m/s

A 1-kg mass at Earth's surface weighs about

10

The force of friction on a sliding object is 10 N. The applied force needed to maintain a constant velocity is

10

Disregarding air drag, how fast must you toss a ball straight upward in order for the ball to remain in the air for a total time of 2 s?

10 m/s

If a freely falling object were somehow equipped with a speedometer, its speed reading would increase each second by about

10 m/s

Neglecting air resistance, when you toss a rock upward, by about how much does its upward speed decrease each second?

10 m/s

A ball is thrown 125 m upward and then falls the same distance back to the Earth. Neglecting air resistance, its total time in the air is about

10 s

A gun with a muzzle velocity of 100 m/s is fired horizontally from a tower. Neglecting air resistance, where will the bullet be 1 s later?

100 m downrange

The current through a 10 ohm resistor connected to a 120-V power supply is

12 A

A ball is moving at 4 m/s and has a momentum of 48 kg ∙ m/s. What is the ball's mass?

12 kg

If you exert 100 J in 50 s, your power output is

2 W

A 2-kg mass has 40 J of potential energy with respect to the ground. Approximately how far is it located above the ground?

2 m

The average speed of a horse that gallops a distance of 10 km in a time of 30 min is

20 km/h

A car has a mass of 1000 kg and accelerates at 2 m/s2. What is the magnitude of the force exerted on the car?

2000

What horizontal applied force will accelerate a 400-kg crate at 1 m/s2 across a factory floor against a friction force half its weight?

2400

Exert 100J in 50s, and your power output is

2w

On the surface of Jupiter, where the acceleration due to gravity is about three times that of Earth, a 100-kg rock would have a weight of about

3000

A TV set is pushed a distance of 2 m with a force of 20 N that is in the same direction as the set moves. How much work is done on the set?

40 J

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

Suppose a jumper claims a hang time of 2 s. Then that jumper must be able to jump a height of

5 m

A projectile is launched vertically at 50 m/s. If air resistance is negligible, its speed upon returning to its starting point is

50 m/s

What is the force of gravity on a 500-N woman standing on Earth's surface?

500

An object is pulled northward with a force of 10 N and southward with a force of 15 N. The magnitude of the net force on the object is

5N

A 10-N falling object encounters 4 N of air resistance. The magnitude of the net force on the object is

6

A car accelerates from rest at 2 m/s2. What is its speed 3 s after the car starts moving?

6 m/s

An object is in free fall. At one instant, it travels at a speed of 50 m/s. Exactly 1 s later, its speed is about

60 m/s

A 2-kg mass is held 4 m above the ground. What is the approximate potential energy of the mass with respect to the ground?

80 J

Surrounding every moving electron is

Both A and B

What quantity does Work change?

Energy

You are dragging a block on a surface with friction at a steady speed of 2 m/s and exert a force of 5N to do so. What is the force of friction? Why?

Equal to 5N, because the force of friction should exactly balance out the force that you apply on a block, so that there is no net force acting on the block.

Which pole of a compass needle points to a south pole of a magnet?

North Pole

Which has a greater momentum - a heavy truck at rest or a moving skateboard?

The moving skateboard.

What does ⅀F = 0 mean?

The vector sum of all the forces that act on an object equals zero> The forces cancel!

Someone standing at the edge of a cliff throws one ball straight up and another ball straight down at the same initial speed. Neglecting air resistance, the ball to hit the ground below the cliff with the greatest speed will be the one initially thrown

They will both hit with the same speed.

An Earth satellite is simply a projectile freely falling around the Earth.

True

What do we call the quantity (Force) x (Distance)?

Work

Which has zero acceleration?

all of the above

Which has the greater mass?

an automobile battery

Rapid changes of a magnetic field induces

an electric field

The amount of air resistance that acts on a wing suit flyer (and a flying squirrel) depends on the flyer`s

area and speed

A bullet fired from a rifle begins to fall

as soon as it leaves the barrel

A heavy object and a light object are dropped at the same time from rest in a vacuum. The heavier object reaches the ground

at the same time as the lighter object

A very massive object A and a less massive object B move toward each other under the influence of gravitation. Which force, if either, is greater?

both forces are the same

Electrons move in an electrical circuit

by interacting with an established electric field

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

An open freight car rolls friction-free along a horizontal track in a pouring rain that falls vertically. As water accumulates in the car, its speed

decreases

What quantities are necessary to determine a vector quantity?

direction and magnitude

The two measurements necessary for calculating average speed are

distance/time

An object is propelled along a straight-line path by a force. If the net force were doubled, its acceleration would

double

A freight train rolls along a track with considerable momentum. If it rolls at the same speed but has twice as much mass, its momentum is

doubled

An object is placed exactly halfway between Earth and the Moon. The object will fall toward the

earth

An object at rest may have

energy

Compared to the huge force that attracts an iron tack to a strong magnet, the force that the tack exerts on the magnet is

equally huge

Magnet A has twice the magnetic field strength of magnet B, and at a certain distance pulls on magnet B with a force of 100 N. The amount of force that magnet A exerts on magnet B is

exactly 100 N

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 to

follow a straight-line path

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

force that the ball exerts on the bat

Alternating current is normally produced by a

generator

Momentum is transferred to the ground when an apple falls on it. The momentum absorbed by the ground is

greater than that of the apple only if the apple bounces

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

According to Newton, the greater the masses of interacting objects, the

greater the gravitational force b/w them

The direction of a gravitational field is

in the same direction as gravitational attraction.

If an object's mass is decreasing while a constant force is applied to the object, the acceleration

increases

Two objects move toward each other because of gravity. As the objects get closer and closer, the acceleration of each

increases

One object has twice as much mass as another object, and also has twice as much

inertia

What is the name of property of objects to maintain their states of motion?

inertia

A bullet is dropped into a river from a very high bridge. At the same time, another bullet is fired from a gun, straight down towards the water. Neglecting air resistance, the acceleration just before striking the water

is the same for each bullet

Whenever the net force on an object is zero, its acceleration

is zero

The ball are rolling on Inclined Plane. How does the distance traveled by the ball in the second half second compare with the distance traveled by the ball in the first half second?

it increases

A rock is thrown vertically into the air. At the very top of its trajectory, the net force on it is

its weight

Compared to a recoiling rifle, the bullet fired has a greater

kinetic energy

A force is a vector quantity because it has both

magnitude and direction

A kilogram is a measure of an object's

mass

Two objects, A and B, have the same size and shape, but A is twice as heavy as B. When they are dropped simultaneously from a tower, they reach the ground at the same time, but A has greater

momentum

What does an object have when moving that it doesn't have when at rest?

momentum

A moving object has

momentum, velocity, and speed

When an increase in speed doubles the momentum of a moving body, its kinetic energy.

more than doubles

When an increasing in speed doubles the momentum of moving body, its kinetic energy

more than doubles

Magnetism is due to the motion of electrons as they

move around the nucleus and spin on their axes

An object that has kinetic energy must be

moving

The source of all magnetism is

moving electric charge

An Earth satellite is in an elliptical orbit. The satellite travels fastest when it is

nearest the Earth

If you push for an hour against a stationary wall, no work is done

on the wall

The headlights, radio, and defroster fan in an automobile are connected in

parallel

The intensity of cosmic rays bombarding Earth's surface is largest at the

poles

A projectile is fired vertically from the surface of Earth at 8 km/s. The projectile will

rise and fall back to Earth's surface

The force exerted on the tires of a car to directly accelerate it along a road is exerted by the

road

Compared with the mass of a certain object on Earth, the mass of the same object on the Moon is

same

A bullet is dropped from the top of the Empire State Building while another bullet is fired downward from the same location. Neglecting air resistance, acceleration is greatest for the

same for each

In an electric circuit, the safety fuse is connected to the circuit in

series

Two identical arrows, one with twice the kinetic energy of the other, are fired into a hay bale. The faster arrow will penetrate

twice as far as the slower arrow

When an object is lifted 10 m, it gains a certain amount of potential energy. If the same object is lifted 20 m, its potential energy gain is

twice as much

An object is raised above the ground gaining a certain amount of potential energy. If the same object is raised twice as high, it gains

twice as much potential energy

One end of a long uniform log is raised to shoulder level. An identical log is raised at its center to the same level. Raising the second log requires about

twice as much work

Which direction does a table push a book resting on it?

up

Which depends on gravity - weight or mass?

weight

Recoil is noticeable if we throw a heavy ball while standing on roller skates. If instead we go through the motions of throwing the ball but hold onto it, our net recoil will be

zero