Physical Science Exercise 3
The horizontal speed of a projectile is influenced by gravity.
False
The pressure in liquid decreases with depth.
False
In elliptical orbit, the satellite's speed and distance from the center of the Earth are different at different points.
True
It takes a relatively short time to boil water at higher altitude than at sea level.
True
Salty water is denser than fresh water.
True
The density of fish is equal to the density of water.
True
Water pressure is height dependent
True
If the mass of an object were to double while its volume remains the same, its density would:
double
The density of a fish is:
equal to the density of water
According to Newton, the greater the masses of interacting objects, the:
greater the gravitational force between them
When the distance between two stars decreases by half, the force between them:
increases four times as much
An Earth satellite is in an elliptical orbit. The satellite travels faster when it is:
nearer to Earth
Ice tends to form at the:
surface of bodies of water
A machine puts out 100W of power for every 1000W put into it. The efficiency of the machine is:
10%
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
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 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
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
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
A coin and a feather dropped in a vacuum will have the same momentum.
False
A floating object displaces a fluid equal to its own volume.
False
According to Newton, the grater the distance between masses of interacting objects, the:
Less gravitational force between them
Force per unit area is called:
Pressure
Any object that moves through the air or through space under the influence of gravity is called:
Projectile
Compared to a bar of pure gold, the density of a pure gold ring is:
The same
A coin and a feather dropped in a vacuum fall at equal acceleration.
True
A completely submerged object dispalces its volume of fluid
True
If you do work on an object in half the time, your power output is:
Twice the usual output
A moving object has:
all of these
A bullet fired from a rifle begins to fall:
as soon as it leaves the rifle
A rock is thrown upward at angle of 50 degree with respect to the horizontal. As it rises, its vertical component of velocity:
decreases
the amount of matter per unit volume is called:
density
The critical speed at which a projectile outruns gravity is called:
escape speed
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
Atmospheric pressure is:
higher at sea level than at the top of a very high mountain
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
Ice floating on water indicates that the density of ice is:
less than the density of water
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 to the period of satellites in orbit closer to the Earth, the period of satellites in orbit far from the Earth is:
longer
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
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
An earth satellite is simply a projectile freely falling around the Earth.
true
An object that has kinetic energy must be moving.
true
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
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
When a checolate bar is cut in half, its density is:
unchanged
A feather and a coin dropped in a vacuum fall with equal:
Acceleration
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 ship floats higher on fresh water than on salty water
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
What is the weight of water displaced by a 100-ton floating ship?
100 tons
A car moves 4 times as fast as another identical car. compared to the slower car, the faster car has:
16 times the KE
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 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
A projectile hits the surface of the Earth at some point, if its speed is:
<8000m/s
Inside a freely falling runaway elevator, your:
Apparent Weight is zero
The principle which states that an immersed body is buoyed by a force eaual to the weight of the fluid displaced is:
Archimedes principle
In the vacuum of outer space, there is no:
Atmospheric pressure
If a loaf of bread is compressed, its:
Density increases
Atmospheric pressure is higher at the top of a mountain than at sea level.
False
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
Ice tends to form at the bottom of bodies of water.
False
If you do work on an object in ahlf the time, your power output is also half the usual power.
False
Kinetic energy is energy of an object because of its location.
False
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
An astronaut in orbit feels weightless.
True
An earth satellite is simply a projectile freely falling around the Earth.
True
Atmospheric pressure is higher at sea level than on top of very high mountain.
True
Ice floating on water indicates that the density of ice is higher than the dendity of water.
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
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 feeling encountered in a free fall, wherein a support force is lacking, is called:
Weightlessness
Earth satellites are typically more than 100km high, so as to be above the Earth's:
atmosphere
The pressure exerted against bodies in the atmosphere, resulting from the weight of air pressing down from above, is called:
atmospheric pressure
any device that measure atmospheric pressure
barometer
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
Water pressure is greatest against the:
bottom of a submerged object
The net upward force that a fluid exerts on an immersed object is called:
buoyant force
A car that travels twice as fast as another , when braking to a stop, will skid:
four times as far
Two objects move towards each other because of gravity. As the objects get closer, the force between them:
increases
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
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
