Physical Science Test 2
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
The faster a fluid moves, the A) greater its internal pressure. B) less its internal pressure. C) pressure doesnt change
B) less its internal pressure.
Which requires more work: lifting a 50 kg sack vertically 2 m or lifting a 25 kg sack vertically 4 m? or the same
Both require the same amount of work
When gas in a container is squeezed to half its volume, its density
doubles
If the radius of the Earth somehow decreased with no change in mass, your weight would
increase
Two objects move toward each other because of gravity. As the objects get closer and closer, the force between them
increases
buoyant force is greatest on a submerged: 1 cubic centimeter block of lead 1 cubic centimeter block of aluminum is the same on each
is the same on each
Consider two planets in space that gravitationally attract each other. If the masses of both planets are doubled, and the distance between them is also doubled, then the force between them is: one quarter half as much twice as much four times as much none of these
none of these
When you jump from an elevated position you usually bend your knees upon reaching the ground. By doing this, the time of the impact is about 10 times more than for a stiff-legged landing. In this way the average force your body experiences is
reduced by 10 times
Which has greater kinetic energy, a car traveling at 30 km/h or a car of half the mass traveling at 60 km/h?
the 60 km/h car
The reason a life jacket helps you float is that: the jacket makes you weigh less the jacket has the same density as an average human the jacket repels water if you sink, the jacket sinks the density of both you and the jacket together is less than your density alone
the density of both you and the jacket together is less than your density alone
Compared to the buoyant force of the atmosphere on a 1-liter helium-filled balloon, the buoyant force of the atmosphere on a nearby 1-liter solid iron block is
the same
Planets would crash into the sun if it weren't for
their tangential velocities
A 1-kg chunk of putty moving at 1 m/s collides with and sticks to a 5-kg bowling ball that is initially at rest. The bowling ball and putty are then set in motion with a momentum of
1 kg*m/s
A 5-kg fish swimming at a speed of 1 m/s swallows an absent-minded 1-kg fish swimming toward it at 4 m/s. The speed of the larger fish after lunch is
1/6 m/s
A machine puts out 100 W of power for every 1000 W put into it. The efficiency of the machine is
10%
what is the weight of water displaced by a 100 ton floating ship?
100 tons
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
a rock suspended by a weighing scale weighs 5 N out of water and 3 N when submerged in water. What is the buoyant force on the rock?
2 N
Consider a hydraulic press. When the input piston is depressed 20cm, the output piston is observed to move 1 cm. On the same press, an input force of 1N can raise no more than
20 N
A bow is drawn so that it has 40 J of potential energy. When fired, the arrow will ideally have a kinetic energy of
40 J
Throw an object at an angle upward. With no gravity it will follow a straight-line path. But because of gravity, at the end of 1 s, it is: 5 m below the straight line 10 m below the straight line 15 m below the straight line
5 m below the straight line
Using 1000 J of work, a toy elevator is raised from the ground floor to the second floor in 20 seconds. How much power does the elevator use?
50 W
A projectile is launched vertically upward 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 N
A diver who weighs 500 N steps off a diving board that is 10 m above the water. The diver hits the water with kinetic energy of
5000 J
A car traveling along the highway needs a certain amount of force exerted on it to stop. More stopping force may be required when the car has: more mass more momentum less stopping distance all of these none of these
all of these
a moving object has: all of these speed velocity momentum energy
all of these
Inside a freely-falling runaway elevator, your: acceleration is zero apparent weight is zero gravitational interaction with the Earth is zero all of these none of these
apparent weight is zero
a bullet fired from a rifle begins to fall:
as soon as it leaves the barrel
You're driving down the highway and a bug spatters into your windshield. Which undergoes the greater change in momentum? the bug your car both the same
both the same
on a windy day, atmospheric pressure: decreases increases remains unchanged
decreases
wind blowing over the top of a hill: increases atmospheric pressure there decreases it does not affect atmospheric pressure there
decreases it
The power expended when a barbell is raised 2.0 m in 2 s is : 1 W 4W 8 W dependent on the mass of the barbell
dependent on the mass of the barbell
The Bernoulli effect causes passing ships to be drawn together when the ships are close and moving in : the same direction the opposite direction either the same or opposite
either the same or opposite
blood pressure is normally greater in your
feet
How far must one travel to get away from Earth's gravity?
forget it; you cant travel far enough
According to Newton, the greater the masses of interacting objects, the: less the gravitational force greater the gravitational force between them greater the force between them by the square of the masses
greater the gravitational force between them
If the volume of an object were to double while its mass stays the same, its density would
halve
A block of Styrofoam floats on water while a lead block of the same size block lies submerged in the water. The buoyant force is greatest on the
lead
Pumice is a volcanic rock that floats. Its density is
less than the density of water
a "weightless" astronaut in an orbiting shuttle is : shielded from Earth's gravitational field beyond the pull of gravity pulled only by gravitation to the shuttle which cancels the Earth's gravitational pull like the shuttle, pulled by Earth's gravitation none of these
like the shuttle, pulled by Earth's gravitation
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
If the speed of a moving object doubles, then what else doubles? momentum kinetic energy acceleration all of these none of these
momentum
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 speed acceleration momentum all of these none of these
momentum
a moving object on which no forces are acting will continue to move with constant
momentum
The difference between impulse and impact force involves the: distance the force acts time the force acts difference between acceleration and velocity mass and its effect on resisting a change in momentum
time the force acts
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
A 1000 kg car and a 2000 kg car are hoisted the same distance in a gas station. Raising the more massive car requires: less work as much work twice as much work four times as much work more than four times as much work
twice as much work
If you push an object just as far while applying twice the force, you do:
twice as much work
If you do work on an object in half the time, your power output is: twice the usual power output half the usual power output the same power output no answer text provided
twice the usual power output
When a chocolate bar is cut in half, its density is
unchanged
The reason that buoyant force acts upward on a submerged object is that: it acts in a direction to oppose gravity if it acted downward, nothing would float the weight of fluid displaced reacts with an upward force upward pressure against the bottom is greater than downward pressure against the top of the submerged object
upward pressure against the bottom is greater than downward pressure against the top of the submerged object
a dam is thicker at the bottom than at the top because: water is denser at deeper levels water pressure is greater with increasing depth surface tension exists only on the surface of liquids it looks better none of these
water pressure is greater with increasing depth
A rising balloon is buoyed up with a force equal to the
weight of air it displaces
