Ability To Orbit

Why do astronauts appear weightless on the moon?

Astronauts appear to weightless on the moon because there is no gravity, or there is less gravity than there is on Earth.

If it weren't for Newton's _____ law, regarding inertia, the planets would travel in a straight line into space. Gravity is the outside force that keeps the planets in orbit about the Sun.

First

Linda has a cup of coffee sitting in the cup holder in her car. She has to suddenly slam on her brakes and stop. The cup remained in the cup holder, but the coffee splashed and spilled everywhere. Newton's _____ law can best describe why this happened.

First

When a mass increases, its gravitational force _______.

Increases

According to Newton's first law, massive objects have _____ inertia than small objects, which means it takes more force to move bigger things than smaller ones.

More

Andre the Giant and Thumbelina are standing in the middle of an ice-skating rink facing each other. Andre the Giant pushes Thumbelina and she goes sliding, but Andre also slides a bit backwards. Why did this happen?

Newton's third law

According to the universal law of gravity, everything has a gravitational force.

True

The strength of gravitational force is dependent on the masses of and distance between two objects.

True

It was a children versus grown-ups competition at school. One event required the adult to throw a basketball as far as he could. When it was the child's turn, he had to throw a baseball instead. The event coordinator said, "It's only fair!" Based on Newton's laws, was this event fair?

Yes, because an adult can apply more force than a child can. Making the adult's object bigger than the child's object helps to even out the acceleration.

Select the object that has the most gravitational force.

a bowling ball

According to Newton's third law, forces come in pairs. There is ________ and an equal and opposite ________ .

an action reaction

The gravitational force decreases as the _____ between two objects increases.

distance

The planets are pulled toward the Sun by _____.

gravity

According to Newton's second law, the acceleration of an object depends on its ________ and the amount of _______ applied to it.

mass force

Jupiter is 317 times more massive than the earth. Its gravitational attraction is _____ Earth's.

stronger than