Chapter 4 Review Physics
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
Part complete Two projectiles are fired at equal speeds but different angles. One is fired at an angle of 30° and the other at 60°. With no air resistance, the projectile to hit the ground first will be the one fired at
30
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
For each 8-km segment of a satellite in close Earth orbit, the "drop" toward Earth is about
5 m
What is the force of gravity on a 500-N woman standing on Earth's surface?
500 N
The hang time of an athlete who moves horizontally 2 m during a 1.25 m high jump is
About 1 s
If Earth's mass somehow doubles with no change in its size, and your mass remains the same, your weight
Also doubles
Traveling from Earth to the Moon requires that a rocket have
Any sustained speed if time isn't a factor
An astronaut lands on a planet that has the same mass as Earth but half the diameter. How does the astronaut's weight differ from that on Earth?
Astronaut has four times as much weight as on Earth
Where do you weigh more - at sea level or atop one of the peaks of the Rocky Mountains?
At sea level because your distance to the center of the Earth is least at sea level
In the vacuum of outer space far from our sun, there is no
Atmospheric pressure
Acceleration is greatest for a satellite in elliptical orbit when it is
Closest to Earth
When the distance between a pair of stars doubles, the force between them...
Decreases to one-quarter as much
If the masses of two planets doubles and the distance between them reduces by half, the force between them would be...
None of the above
What holds Earth satellites up so they don't crash into Earth?
Nothing, they continually fall fast enough around Earth not to crash
The fastest moving planet in a solar system is the
Planet nearest the sun
Newton discovered
That gravity is universal
Planets wobble in their orbits due to
The gravitational attraction to other planets
After a rock that is thrown straight up reaches the top of its path and is starting to fall back down, its acceleration is
The same as it was at the top of its path
Nellie tosses a ball upward at an angle. Assuming no air resistance, which component of velocity changes with time?
The vertical component
A satellite in an elliptical orbit travels at constant
None of the above
Escape speed from Earth is
11.2 km/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
When the distance between a pair of stars decreases by half, the force between them
Increases to four times as much
Earth is gravitationally pulled toward
Mars, Jupiter and the Sun
Compared to other fundamental forces, the Universal Gravitational Constant G indicates gravity to be a relatively
Weak force
Inside a freely-falling elevator your
Weight is zero
With no air resistance, a projectile fired at 50 has the same range as if it were fired at
40
Phil stands at rest with both feet on a scale that reads 500 N. After he gently lifts on foot, the scale reads
500 N
A dropped ball gains speed because
A gravitational force acts on it
The Moon falls toward Earth in the sense that it falls...
Beneath the straight-line path it would take without gravity
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
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
When a satellite travels at constant speed, its shape is a
Circle
An object is placed exactly halfway between the Earth and the Moon. The object will fall toward the
Earth
If the sun were twice as massive,
Earth's pull on the sun would double, its pull on the Earth would double
Newton did not discover gravity, for early humans discovered that whenever they fell. What Newton did discover is that gravity
Extends throughout the universe
Your weight is equal to mg when you are
Firmly supported on a horizontal surface an in equilibrium
The sun is spherical due to
Gravitation
At what part of an elliptical orbit does an Earth satellite have the greatest speed? The least speed?
Greatest when closest. Least when furthest
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
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
A space vehicle can outrun Earth's gravity, but can it get entirely beyond Earth's gravity?
No, Earth's gravity extends to infinity, decreasing as the inverse square of the distance
When a projectile achieves escape speed from Earth, it _______
Outruns the influence of Earth's gravity, but is never beyond it
Without air resistance, a projectile fired horizontally at 8 km/s from a mountain top will
Return to its starting position and repeat its falling behavior, trace a curve that matches Earth's curvature, and accelerate downward at g as it moves horizontally
A projectile that is fired vertically at 5 km/s from the Earth's surface will
Rise and fall back to Earth's surface
A projectile that is fired vertically at 8 km/s from Earth's surface will
Rise and fall back to Earth's surface
Occupants of the International Space Station experience weightlessness due to
The absence of a support force
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
How far must one travel to completely be beyond Earth's gravity?
You can't travel far enough
