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