Astronomy #4

which one of the following describes an object that is accelerating?

A car going around a circular track at a steady 100 miles per hour.

Suppose you visit another planet:

Your mass would be the same as on Earth, but your weight would be different.

Which person is weightless?

A child in the air as she plays on a trampoline.

Consider the statement "There's no gravity in space." This statement is:

completely false

If you want to make a rocket turn left, you need to:

Fire an engine that shoots out gas to the right.

Compared to its angular momentum when it is farthest from the Sun, Earth's angular momentum when it is nearest to the Sun is:

the same

the gravitational potential energy of a contracting interstellar cloud

gradually transforms into other forms of energy

If Earth were twice as far from the Sun, the force of gravity attracting Earth to the Sun would be

one quarter as strong

According to the law of universal gravitation, what would happen to Earth if the Sun were somehow replaced by a black hole of the same mass?

Earth's orbit would not change

If the Moon were closer to Earth, high tides would

Be higher than they are now

speed

the rate at which an object is moving

velocity

speed in a certain direction

acceleration

a change in velocity (a change in either speed or direction)

momentum

mass*velocity

force

can change an objects momentum causing it to accelerate

What are Newtons three laws of motion

1)an object moves at a constant velocity if there is no net force acting upon it
2)force=mass*acceleration
3)for any force there is always an equal and opposite reaction force

conservation of momentum

an objects momentum cannot change unless it transfers angular momentum to another object

3 types of energy