Physical Science Chapter 4
If a projectile is fired straight up at a speed of 10 m/s, neglecting air resistance, the total time to return to its starting position is
2 s
If there were no gravity, a ball thrown upward at an angle would follow a straight-line path. Due to gravity, however, at the end of 2 s it is
20 m below the straight line
A softball player determines her pitching speed by throwing a ball horizontally from an elevation of 20 m above the ground. The ball lands 50 m downrange. What is her pitching speed?
25 m/s
For each 8-km segment of a satellite in close Earth orbit, the "drop" toward Earth is about
5 m
Your weight is equal to mg when you are
Firmly supported on a horizontal service and in equilibrium.
The tangential velocity of an Earth satellite is its velocity
Parellel to the surface of Earth
Perturbations of planets are due to
interplanetary forces
Your weight is defined to be the force
you exert against a supporting surface
Inside a freely-falling elevator your
Weight is zero
You can experience weight
all of the above
Neglecting air resistance, after a ball leaves your hand when you toss it upward, the force on it
is only the force due to gravity, always directed downward
A projectile is launched straight upward at 50 m/s. Neglecting air resistance its speed upon returning to its starting point is
50 m/s
Phil stands at rest with both feet on a scale that reads 500 N. After he gently lifts one foot, the scale reads
500 N
What is the force of gravity on a 500-N woman standing on Earth's surface?
500 N
According to Newton, the greater the masses of interacting objects, the Select one:
Greater than the gravitational force between them.
With no air resistance a projectile fired horizontally maintains its horizontal component of velocity because
No horizontal force acts on it.
If the masses of two planets doubles and the distance between them also doubles, the force between them would be
None of the above
The force of gravity on a bowling ball rolling along a horizontal surface doesn't change its speed because the force is
Perpendicular to its direction of motion
As a bowling ball that rolls off the edge of a table falls, its horizontal component of motion
Remains constant
A woman who normally weighs 400 N stands on top of a very tall ladder so she is one Earth-radius above Earth's surface. What is her weight there?
100 N
A ball is thrown horizontally from the top of a tall cliff. Three seconds later, the ball has fallen a vertical distance of
45 m
A stone is thrown horizontally from the top of a cliff. One second after leaving your hand it drops a vertical distance of
5 M
An object is placed exactly halfway between the Earth and the Moon. The object will fall toward the
Earth
The planet Jupiter is about 300 times as massive as Earth, yet on its surface you would weigh only about 3 times as much because
Jupiters radius is ten times Earths radius
According to Newton, the greater the distance between gravitationally interacting objects, the
Less than the gravitational force between them.
For the astronauts inside an orbiting space vehicle the force of gravity that acts on them is
Mainly due to Earth below
According to Newton, the closer gravitationally interacting objects are to each other, the
More the gravitational force between them.
The force of gravity on a satellite in circular orbit doesn't change its speed because the force is
Perpendicular to its direction of motion
The force of gravity acts on all apples on an apple tree. Some apples are twice as far from the ground. Such twice-as-high apples of the same mass, have
Practically the same weight
A rock is thrown upward at 50° with respect to the horizontal. As it rises, its horizontal component of velocity
Remains unchanged
Weight can be simulated in a space vehicle if the vehicle is
Rotating
This chapter states a link between Newton's Universal Law of Gravity and
The US constituition
Strictly speaking, when you step off a curb you are momentarily
Weightless
An airplane flying overhead drops a care package directly over Mike at rest in his Corvette. Neglecting air resistance, the package will land
Well ahead of Mike and his corvette
A "weightless" astronaut in an orbiting space vehicle is
Without a support force
Passengers in a high-flying jumbo jet feel their normal weight in flight, whereas passengers in an orbiting space vehicle do not because they are
Without support forces
A dropped ball gains speed because
a gravitational force acts on it
You experience weightlessness
all of the above
If Earth's mass somehow doubles with no change in its size, and your mass remains the same, your weight
also doubles
If your mass doubles, your weight
also doubles
A bullet fired from a rifle begins to fall
as soon as it leaves the barrel
Each of us weighs slightly less inside the ground floor of a skyscraper than we do on the ground away from the skyscraper because the
mass of the building attracts us upward slightly.
The amount of gravitational force that acts on a space vehicle that orbits Earth is
nearly as much as the vehicle's weight on Earth's surface.
An object is thrown vertically into the air. Because of air resistance, the time for its descent will be
Longer than the ascent time
Wobbles in the path of Uranus led to the discovery of
Neptune
Why doesn't the Moon fall toward Earth like apples do?
moon does fall but due to its tangential motion it also falls around Earth
Pioneer 10 was able to escape the solar system by
"bouncing off" Jupiter like a tennis ball bouncing off an approaching tennis racket.
Consider a monkey wrench released at rest at the far edge of the solar system that drops to Earth by virtue of only Earth's gravity. The wrench will strike Earth's surface with a speed of about
11 km/s
Escape speed from Earth is
11.2 km/s
A supplier wants to make a profit by buying gold by weight at one altitude and selling it at the same price per newton at another altitude. The supplier should
Buy at a high altitude and sell at a low altitude.
The Universal Gravitational Constant G was first measured by
Cavendish
Acceleration is greater for a satellite in elliptical orbit when it is
Closest to Earth
If Earth's mass decreased to one-half its original mass with no change in radius, your weight would
Decreases to one-half
A vertically oriented rocket that is able to sustain a continuous upward velocity of 8 km/s will
Eventually escape from Earth
An Earth satellite in an elliptical orbit travels slowest when it is
Farthest from the Earth
Compared to the speed a satellite loses when traveling from nearest to farthest points from Earth, the speed gained when returning from farthest to nearest is
The same
The planet Neptune was discovered by perturbations of
Uranus
Dwarf planet Pluto was discovered by perturbations of
Uranus and Neptune
Compared to other fundamental forces, the Universal Gravitational Constant G indicates gravity to be a relatively
Weak force
The hang time of an athlete who moves horizontally 2.0 m during a 1.25-m-high jump is
About 1 s
As a bowling ball that rolls off the edge of a table falls, its vertical component of motion
Increases
After a stone that is thrown straight up reaches the top of its path and then falls downward, its acceleration is
The same as at the top of its path
An outcome of universal gravitation is that
all of the above
The Moon continually falls toward Earth, but doesn't get closer because
its tangential velocity causes it to fall around as well as toward Earth.
The radial velocity of an Earth satellite is its velocity
perpendicular to the surface of Earth.
Newton discovered
that gravity is universal
A bullet fired horizontally hits the ground in 0.5 s. If it had been fired with twice the velocity it would have hit the ground in
0.5 s
If a projectile is fired straight up at a speed of 10 m/s, neglecting air resistance, the time it takes to reach the top of its path is
1 s
A gun with a muzzle velocity of 100 m/s is fired horizontally from a tower. Neglecting air resistance, how far downrange will the bullet be 1 s later?
100 M
A softball player determines her pitching speed by throwing a ball horizontally from an elevation of 5 m above the ground. The ball lands 20 m downrange. What is her pitching speed?
20 m/s
Ignoring air resistance, what maximum speed can be given to a horizontally moving tennis ball as it clears the net 1.25 m high to remain within the edge of the court, which is 12.0 m from the bottom of the net?
24 m/s
Earth satellites are typically more than 100-km high so as to mainly be above the Earth's
Atmosphere
An airplane flies at 40 m/s at an altitude of 50 m. The pilot drops a heavy package that falls to the ground below. Neglecting air resistance, the package will land
Beneath the plane
A very massive object A and a less massive object B move toward each other under the influence of gravity. Which force, if either, is greater?
Both forces on each other are the same.
If the radius of the Earth somehow increased with no change in mass, your weight would
Decrease
If Earth's mass somehow decreased with no change in its radius, your weight would
Decrease also
A rock is thrown upward at 50° with respect to the horizontal. As it rises, its vertical component of velocity
Decreases
When the distance between a pair of stars doubles, the force between them
Decreases by one-quarter
Nellie tosses a ball upward at an angle. Assuming no air resistance, which component of velocity changes with time?
The vertical component
Consider two planets in space that gravitationally attract each other. If the mass of one planet is doubled, and the distance between them doesn't change, then the force between them is
Twice as much
Planets wobble in their orbits due to
the gravitational attraction to other planets
Inside a freely-falling elevator you would have no
weight
In the vacuum of outer space far from our Sun, there is no
Atmospheric pressure
A hunter fires a bullet from a horizontally—held rifle while simultaneously dropping another bullet from the side of the rifle. The bullet to hit the ground first is
Both hit at the same time
Air resistance on a high-speed projectile shortens its
Both of these
An Earth satellite is simply a projectile
freely falling around the earth
The Sun is spherical due to
gravitation
A projectile is launched at an angle of 15° above the horizontal and lands downrange. With no air resistance, what other projection angle for the same speed would produce the same downrange distance?
75 degrees
A ball rolls off the edge of a table at the same time another ball drops vertically from the same table. The ball to hit the floor first is the
Both hit at the same time.
One second after a ball rolls off the edge of a horizontal surface at a speed of 10 m/s,
Both of these
The identities of dark energy and dark matter are
Both of these
How far away from Earth must one travel to completely be beyond Earth's gravity?
Forget it, you can't travel far enough.
At some point between Earth and the Moon, the forces due to gravity on a space traveler would be the same when this point is
nearer the Moon
Planets would crash into the Sun if it weren't for
their tangential velocities
An Earth satellite in an elliptical orbit travels fastest when it is
Nearest the Earth
A satellite in an elliptical orbit travels at constant
None of the above
Escape speed for a rocket is greatest from
the Sun
The fastest moving planet in a solar system is the
the planet nearest the sun
The speeds of the planets about the Sun depend on
their distances from the sun
With no air resistance, a projectile fired at 60° has the same range as if it were fired at
30 degrees
With no air resistance, a projectile fired at 50° has the same range as if it were fired at
40 degrees
If there were no gravity, a ball thrown upward at an angle would follow a straight-line path. Due to gravity, however, at the end of 1 s it is
5 m below the straight line
The parabolic path of a cannonball fired from a mountain top is actually
A segment of an ellipse
A satellite near Earth makes a full circle in about 90 minutes. Much farther from Earth, say at the distance to the Moon, time for a full circle would be
About 28 days
Without air resistance, a projectile fired horizontally at 8 km/s from a mountain top will
All of the above
The circular path of a satellite orbiting Earth is characterized by a constant
All the above
Traveling from Earth to the Moon requires that a rocket have
Any sustained speed if time isn't a factor
The International Space Station orbits at an average 360-km altitude so that it is mainly above Earth's
Atmosphere
To drop a package to Earth from a satellite, project it
Behind at satellite speed
The planet Jupiter takes a longer time to travel around the Sun than Earth because Jupiter
Both of these
Two motorcycle stunt drivers, one light and the other much heavier, ride their motorcycles up and off an inclined ramp at identical speeds. They both rise in the air and land downrange. Neglecting air resistance, the one to attain the greatest height and greatest range is the
Both the same
Consider two planets in space that gravitationally attract each other. If the masses of both planets are doubled, and the distance between them doesn't change, then the force between them is
Four times as much
Minimal orbit speed about Earth is about 8 km/s. Minimal orbital speed for a satellite about Jupiter would be
Greater than 8 km/s
If the radius of the Earth somehow decreased with no change in mass, your weight would
Increases
Two objects move toward each other due to gravity. As the objects get closer and closer, the acceleration of each
Increases
Two objects move toward each other due to gravity. As the objects get closer and closer, the force between them
Increases
When the distance between a pair of stars decreases by half, the force between them
Increases four times as much.
The Earlybird communication satellite hovers over the same point on Earth's equator indefinitely because
Its orbital period is 24 hours
A lunar month is about 28 days. If the Moon were closer to Earth than it is now, the lunar month would be
Less than 28 days
Minimal orbit speed about Earth is about 8 km/s. Minimal orbital speed for a satellite about the Moon would be
Less than 8 km/s
From Earth, one satellite appears to overtake another. The faster satellite that is seen to overtake the other is
Lower
A lunar month is about 28 days. If the Moon were farther from Earth than it is now, the lunar month would be
More than 28 days
Communications and weather satellites always appear at the same place in the sky because these satellites are
Orbiting Earth with a 24 hour period
The period of a satellite, the time it takes for a complete revolution, depends on the satellite's
Radial distance
A projectile that is fired vertically at 5 km/s from the Earth's surface will
Rise and fall back to Earths surface
A projectile that is fired vertically at 8 km/s from Earth's surface will
Rise and fall back to Earths surface
Escape speed for a rocket is less from
The Moon
Occupants of the International Space Station experience weightlessness due to
The absence of a support force.
A hunter aims a rifle at an angle of 10° above the horizontal. The hunter fires a bullet while simultaneously dropping another bullet from the side of the rifle. The bullet to hit the ground first is
The dropped one
A hunter aims a rifle at an angle of 10° below the horizontal. The hunter fires a bullet while simultaneously dropping another bullet from the side of the rifle. The bullet to hit the ground first is
The fired one
If the Sun were twice as massive,
both of these
Compared with the period of satellites in orbit close to Earth, the period of satellites in orbit far from Earth is
greater
The Moon does not crash into Earth because
moon has a sufficient tangential speed
What holds Earth satellites up so they don't crash into Earth?
nothing, they continually fall fast enough around Earth not to crash
Gravitational force is greater for a satellite in elliptical orbit when it is at the
perigee (closest point)
