practice .1.1

A ball rolling along a smooth sidewalk suddenly rolls onto a grassy area. What will happen to the ball's motion?

• It will roll faster because friction increase.

• It will roll faster because friction decreases,

• It will roll slower because friction increases

• It will roll slower because friction decreases.

The force that keeps satellites in orbit around Earth is:

• magnetic

• friction

• electrical

• gravity

Why does a basketball thrown high in the air come back to the ground after a few seconds?

• air pressure pushes the basketball downwards.

• Earth's gravity pulls the ball downwards

• the sun's gravity pushes the ball downwards.

• air pressure inside the ball forces it downwards.

An object is said to be free fall if:

• the only force acting on its gravity.

• there are no forces acting on it.

• the only force acting on it is friction.

• the object is traveling in a straight line.

The force of acts in the opposite direction of motion of an object

• It causes the moving object to slow and eventually stop

• It causes the moving object to slow and eventually stop.

• It keeps the moving object moving in the same direction forever.

• It causes the moving object to turn around and move in the opposite direction.

The speed and direction of an object's motion is its

• velocity

• inertia

• momentum

• acceleration

If you were to go to the moon, you would weigh less than you do on earth. Why?

• The moon has no gravity

• The moon has less mass than earth

• The moon has more mass than earth.

• You lose mass when you travel through space

Gravitation is a natural phenomenon where?

• objects with greater mass fall slower.

• objects with mass repel each other

• objects with greater mass fall faster

• all objects with mass attract each other.

When a feather and a hammer are dropped at the same time, why does the hammer hit the ground first?

• Heavier objects always fall faster than lighter objects.

• The feather has no mass.

• Air resistance slows the fall of the feather

• Gravity only affects heavy objects

What will happen if you drop a golf ball, a baseball, and a bowling ball at the same instant from the top of a tall building?

• The bowling ball hit the ground first

• The baseball hit the ground first

• The golf ball hit the ground first

• All three balls hit the ground at the same time.