Chapter 4- Gravity and Orbits (COPY OF TEST)

Earth's satellites are typically more than 100km high so as to be above the Earth's(atmosphere, gravitational field, both)

Atmosphere

Newton discovered (gravity, gravity is universal, neither)

Gravity is universal

Planets would crash into the Sun if it weren't for (tangential velocity, vast distances from the sun, inverse-square law, small masses, beyond main gravitation of the Sun)

Tangential Velocity

What is the force of gravity on a 500 N woman standing on Earths surface? (50, 250, 500, 509,8, none of these) N

500 N

A hunter aims a rifle at angle of 10 degrees below the horizontal. The hunter fires a bullet while simultaneously dropping another bullet from the level of the rifle. Which bullet will hit the ground first(dropped, fired one, same time)

Fired one

How far must one travel to get away from the Earth's gravitational field( a region above the Earth's atmosphere, to a region well beyond the Moon, to a region beyond the solar system, forget it; you can't travel far enough)

Forget it!

The fastest moving planet in the solar system is (the smallest, most massive, nearest the sun, farthest the sun, any planet)

the closest planet to the sun

If your mass, the mass of the Earth, and the mass of everything in the solar system were twice as much as it is now, yet everything stayed the same size, your weight on Earth would (be the same, double, quardruple, be the same, be 8 times as much, none)

Quadruple

A projectile is fired straight up vertically at the surface of the Earth at 8 km/s. The projectile will (go circular orbit, rise and fall back to Earth, follow an uncertain path)

Rise and fall back to Earth

A bullet fired horizontally hits the ground in 0.5s. If it had been fired with twice the speed in the same direction, it would have hit the ground in_____(less than 0.5s, more than 0.5s, 0.5s)

0.5s

If the mass of the Earth somehow increased with no change in radius, your weight would (increase also, decease, stay the same)

Increase also

A rock is thrown upward at 50 degrees with respect to the horizontal. As it rises, its horizontal component of velocity( increases ,decreases, remains unchanged)

Increased

Two objects move toward each other because of gravity, As the objects get closer and closer, the acceleration of each (increases, decreases, remains constant)

Increases

Two objects move toward each other because of gravity. As the objects get closer and closer, the force between them (increases, decreases, remains constant)

Increases

It takes Pluto a longer time to travel around the Sun because

It goes slower and has farther to go

Suppose the moon had twice as much mass as it now does and still the orbits the Earth at the same distance. In that case, the ocean bulges on Earth would be( larger, smaller, unequal in size, not significantly different, none of these)

Larger

A bullet fired from a rifle begins to fall( as soon as it leaves the barrel, after air friction reduces the speed, neither)

As soon as it leaves the barrel

A bulled fired horizontally hits the ground in 0.5 s. If it had been fired with twice the speed in the same direction, it would have hit the ground in (Less than 0.5s, greater than 0.5s, 0.5s)

0.5s

The main reason ocean tides exist is that the pull of the Moon( and sun are in conjunction at high tides and opposition at low tides, is greater on oceans closer to the Moon and less on oceans farther from the moon, if greater on Earth because the Moon is closer to Earth, and the sun on the oceans are in opposite directions, none of these)

Is greater on oceans closer to the Moon and less on oceans farther from the Moon

After a rock is thrown straight up reaches the top of its path and is starting to fall back down, its acceleration is(neglecting air resistance) (greater then when it was at the peak, less than it was at its peak, same as it was at the top of its peak)

The same as it was at the top of its path

T or F: An Earth satellite is simply a projectile freely falling around the Earth

True

An object in freefall seems to be ____________ (weightless, slowed by air resistance, speeded up by air resistance, not moving)

Weightless

A projectile is launched at angle of 50 degrees and lands on 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 degrees

With respect to the stars, the Moon( circles the Earth, and the Earth circle each other, remains stationary while the Earth circles about it, does not rotates about its own axis as the Earth does)

And Earth circle each other

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 greatest? ( force on A, force on B, both forces are the same)

Both forces are the same

The path of a projectile on Earth is (straight, always vertical, always horizontal, curved like a parabola)

Curved like a parabola

A rock is thrown upward at 50 degrees with respect to the horizontal. As it rises, its vertical component of velocity( increases, decreases, remains unchanged)

Decreases

An object is placed exactly halfway between the Earth and the Moon. The object will fall toward the (Earth, Moon, neither)

Earth

Which produced a greater tidal effect on ur body, the Moon or a grapefuit sitting on ur head?

The grapefruit

A stone is thrown horizontally from the top of a cliff. One second after it has left ur hand, its vertical distance below the cliff is( 5m, 10m, 15m)

5m

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 (5m below the straight line, 10m below the straight line, 15m below the straight line)

5m below the straight line

A projectile is launcehd at an angle of 15 degrees. What other projectile angle could it be fired at?

75 degrees

The circular orbit is characterized by constant (acceleration, speed, radial distance, all, none of these)

All of these

For the astrounauts inside the orbiting space shuttle, there is no force of Earth's gravity acting on them. This statement is (always true in orbit, sometimes true while in orbit, always false)

Always false

Inside a freely falling elevator, there would be no (gravitational force on you, apparent weight for you, both, neither)

Apparent weight for you

Inside a freely falling runaway elevator, your (acceleration is zero, apparent weight is zero, gravitational interaction with the Earth is zero, all or none)

Apparent weight is zero.

The Earth's gravitational field extends( only above/beyond Earth's surface and cancels inside the Earth, both inside/outside the Earth and the whole universe, neither of these)

Both inside/outside the Earth and the whole universe

If the sun were twice as massive, (its pull on the Earth would double, the pull of the Earth on the Sun would double, both of these, neither)

Both of these

A supplier wants to make a profit by buying metal by weight at one altitude and settling it at the same price/ pound at another altitude. The supplier should( buy at high altitude, sell at low, low altitude/ sell at high, disregard altitude)

Buy at high/ sell at low

A hunter aims a rifle at an angle of 10 degrees above the horizontal. The hunter fires a bullet while simultaneously dropping another bullet from the level of the rifle. Which bullet will hit the ground first?(Dropped one, fired one, both hit at the same time)

Dropped one

According to Newton, the greater the masses of interacting objects, the (less the gravitational force between them, greater the gravitational force between them, greater the force between them by the square of masses)

Greater the gravitational force between them

If the radius of the Earth, somehow decreased with no change in mass, your weight would( increase, stay the same, decrease)

Increase

Minimal orbit speed on Earth is about 8 km/s. The moon would be( less than, greater than, equal to) 8 km/s

Less than 8 km/s

According to Newton, the greater the distance between masses of interacting objects, the( less the gravitational force between them, more the gravitational force between them)

Less the gravitational force between them

____(mass, falling speed, weight, terminal speed) doesn't change with changes in gravity

Mass

ESSAY QUESTION: EXPLAIN THE DIFFERENCES BETWEEN MASS AND WEIGHT. WHAT ARE THE UNITS FOR EACH? WHAT TOOLS ARE USED TO MEASURE EACH?

Mass is measuring the amount of matter an object has and weight measure how much the force of gravity is affecting the mass. Mass is measured in kilograms and weight is measured in Newtons. Mass doesn't change planet to planet, but weight does. A balance is used to measure mass and a spring scale is used to measure weight.

The amt. of gravitational force between objects depends on their (frictional forces, speed and direction, inertia, masses and distance bwteem them)

Masses and distance between them

Minimal orbit speed around Jupiter is (greater than, less than, equal to) 8km/s

More than 8 km/s

An Earth satellite travels in elliptical orbit. It travels fastest when

Nearest the Earth

A satellite in elliptical orbit travels at a constant (velocity, speed, acceleration, all of them, none of them)

None of them

What prevents satellites from falling? (gravity, centripetal force, centrifugal force, absence of air drag, nothing they are constantly falling around the Earth)

Nothing, they are constantly falling around the Earth

Tangential velocity is velocity

Parallel to the surface of the Earth

Accelaration is greatest for a satellite when it is at

Perigee

A weightless astronaut in a orbitting shuttle is( shielded from Earth's gravity field, beyond the pull of gravity, pulled by Earth's gravity, none of these)

Pulled by the Earth's gravitation

Which is more responsible for the ocean tides? (the moon, sun, contribute equally)

The Moon

The Earth is closer to the Sun in January than in July, which accounts for the fact that hte highest high tides in the n. hemisphere( winter, summer, spring, no particular time)

Winter