Physical Science Exercise 1,2,3

The greater the distance from the center of the Earth, the greater will be the weiight of an object.

False

Work is the product of force and time.

False

A feeling encountered in a free fall, wherein a support force is lacking, is called:

Weightlessness

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

nearer to Earth

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

12kg

A car moves 4 times as fast as another identical car. compared to the slower car, the faster car has:

16 times the KE

A stone is thrown horizontally from the top of a cliff. one second after it has left your hand its approximate vertical distance (d=1/2gt2) below the cliff is:

5m

If you do work on an object in half the time, your power output is:

Twice the usual output

The property which specifies the speed and direction of motion an object is called:

Velocity

Which one requires more work: lifting a 50kg sack vertically 2m or lifting a 25kg sack vertically 4m?

both require the same amount of work

A rock is thrown upward at angle of 50 degree with respect to the horizontal. As it rises, its vertical component of velocity:

decreases

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

greater the gravitational force between them

Two objects move towards each other because of gravity. As the objects get closer, the force between them:

increases

The property of things to resist changes in state of motion is called:

inertia

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

is zero

A rock is thrown upward at an angle of 50 degree with respect to the horizontal. As it rises, its horizontal component of velocity:

remains unchanged

A projectile or small celestial body that orbits a larger celestial body is called:

satelite

The force that a object exerts on a supporting surface is called:

support force

The escape speed fro Jupiter is higher than from that of Earth.

False

The speed of an athlete who covers a distance of 80 meters in 10 seconds is:

8m/s

A projectile hits the surface of the Earth at some point, if its speed is:

<8000m/s

A machine puts out 100W of power for every 1000W put into it. The efficiency of the machine is:

10%

A 1kg mass at the Earth's surface weighs about:

10N

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

Acceleration

The rate of change of velocity with time (in magnitude, direction, or both) is called:

Acceleration

The resistive force of friction occurs for:

All of these

Whereas impulse involves the time a force acts, work involves 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, its momentum is:

Doubled

A coin and a feather dropped in a vacuum will have the same momentum.

False

An object at rest has kinetic energy.

False

If the mass of the Earth somehow increased with no change in radius, your weight would:

Increase

A kilogram is a measure of an object's:

Mass

When you stand at rest on a pair of bathroom scales, the reading on the scales will always:

add equal yo your weight

Which one has zero acceleration? An object:

all of the above

A moving object has:

all of these

Compared with 1kg block of solid iron, a 2kg block of solid iron has twice as much:

all of these

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

true

An object that has kinetic energy must be moving.

true

At the same speed of shot, the angle which gives the same range as the launch angle of 65 degree, is:

25 degree

If a projectile is fired straight up at a speed of 10m/s, disregarding air resistance, the total time to return to its starting position is about:

2s

A projectile is thrown into the air at an angle of 50 degree and lands on a target that is at the same level the projectile started. It will also land on the target if it is thrown at an angle of;

40 degree

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

40J

If you do work on an object in ahlf the time, your power output is also half the usual power.

False

The greater the distance from the center of the Earth, the greater will be the weight of an object.

False

The horizontal speed of a projectile is influenced by gravity.

False

It is simply stated as a push or a pull:

Force

A state of fall under the influence of gravity (free from air resistance) is called:

Free fall

The resistive force that opposes motion or attempted motion of an object is called:

Friction

One object that has twice as much mass as another object also has as much:

Gravitational acceleration

The force that supports an object against gravity, often called the normal force, is also known as:

Support force

Your weight is:

The gravitational attraction between you and Earth

A coin and a feather dropped in a vacuum fall at equal acceleration.

True

An astronaut in orbit feels weightless.

True

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

True

If two objects of different masses roll down a slope at the same velocity, the one with the large mass will have a higher momentum.

True

Imoulse is the product of work and time

True

In elliptical orbit, the satellite's speed and distance from the center of the Earth are different at different points.

True

The horizontal speed of a projectile is not affected by gravity.

True

An object that has potential energy may have this energy because of its:

location

When you are in the way of a fast moving object and can't get out of its way, you will suffer a smaller force of impact if you decrease its momentum over a:

long time

Compared with falling on wooden floor, a wine glass may not break when it falls on a carpet floor because of the:

longer time to stop

From Earth, one satellite appears to overtake another. The faster satellite is:

lower

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

the same

A man weighing 200N stands at rest on two bathroom scales so that his weight is distributed evenly over both scales. The reading on each scale is:

100N

A woman who normally weighs 400N stands on top of a very tall ladder so she is one Wart-radius above the Earth's surface. How much would she weigh here?

100N

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

10N

If a car moved at an average speed of 80km/hr; how far would it travel in 3 hours.

240 km

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

500N

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

50m/s

An object is pulled north ward with a force of 10N and south ward with a force of 15N. The magnitude of the net force on the object is:

5N

A projectile is launched at an angle of 15 degree above the horizontal and lands downrange. What other projection angle for the same speed would produce the downrange range distance?

75 degree

Inside a freely falling runaway elevator, your:

Apparent Weight is zero

In the vacuum of outer space, there is no:

Atmospheric pressure

Escape speed from a planet decreases with increase in the mass of the planet.

False

Every 8000 meters, the surface of the Earth drops an approximate vertical distance of 20 meters.

False

Force of impact of a falling object could be reduced by reducing the time over which the force acts.

False

Kinetic energy is energy of an object because of its location.

False

According to Newton, the grater the distance between masses of interacting objects, the:

Less gravitational force between them

Any object that moves through the air or through space under the influence of gravity is called:

Projectile

A measure of how fast something is moving is called:

Speed

Space occupied by a given mass is called:

Volume

The force due to gravity is called:

Weight

The force that an object exerts on a supporting force (or if suspended, on a supporting string), due to the force of gravity is called:

Weight

A bullet fired from a rifle begins to fall:

as soon as it leaves the rifle

Earth satellites are typically more than 100km high, so as to be above the Earth's:

atmosphere

The critical speed at which a projectile outruns gravity is called:

escape speed

A car that travels twice as fast as another , when braking to a stop, will skid:

four times as far

A heavy truck and a small car rolling down a hill at the same speed are forced to stop in the same amount of time. Compared to the force that stops the car, the force needed to stop the truck is:

greater

When the distance between two stars decreases by half, the force between them:

increases four times as much

A ball is thrown vertically into the air. Because of air resistance, its speed when it returns to its starting level, compared to its initial speed is:

less

Compared to the period of satellites in orbit closer to the Earth, the period of satellites in orbit far from the Earth is:

longer

An object that has kinetic energy must be:

moving

The speed of the planets about the Sun depends on:

the edistance of the planets from the sun

If you double the velocity of a moving object with constant mass, its momentum will double.

true

In circular orbit, the speed of a satellite is the same everywhere.

true

Potential energy is energy of an object because of its location.

true

The Moon is simply a projectile circling the Earth.

true

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

twice as much

If you push an object just as far while applying twice the force, you do:

twice as much work

If you push an object twice as far while applying the same force, you do:

twice as much work