a. What is a satellite? b. What causes satellites to stay in orbit rather than falling toward Earth? c. a projectile is thrown with enough velocity to orbit Earth. What would happen if the projectile were thrown with a greater velocity?

Look at the diagram below of two students pulling a bag of volleyball equipment. The friction force between the bag and the floor is $15 \mathrm{~N}$. What is the net force acting on the bag? What is the acceleration of the bag?

Draw a diagram showing the motion of a satellite around Earth. Label the forces acting on the satellite. Is the satellite accelerating?

Explain how force, mass, and acceleration are related by Newton's second law of motion.

Will a flat sheet of paper dropped from a height of $2 \mathrm{~m}$ accelerate at the same rate as a piece of paper crumpled into a ball? Why or why not?

Why do slippery fluids such as oil reduce sliding friction?

The type of force that causes a satellite to orbit Earth is a centripetal force.

a. What is a force? b. How is a force described? c. In a diagram, one force arrow is longer than the other arrow. What can you tell about the forces?

a. Which of Newton's three laws of motion explains how a rocket lifts off? b. How do action-reaction pairs explain how a rocket lifts off? c. As a rocket travels upward from Earth, air resistance decreases along with the force of gravity. The rocket's mass also decreases as its fuel is used up. If thrust remains the same, how do these factors affect the rocket's acceleration?

When an unbalanced force acts on an object, the force a. changes the motion of the object. b. is canceled by another force. c. does not change the motion of the object. d. is equal to the weight of the object.

a. What are the four types of friction? b. What factors affect the friction force between two surfaces? c. What types of friction occur when you ride a bike through a puddle?

a. State Newton's third law of motion. b. According to Newton's third law of motion, how are action and reaction forces related? c. What would happen if you tried to catch a ball when you were standing on roller skates?

In the balloon diagram above, why don't the two forces cancel each other out? A They are not equal. B They both act on the air. C They both act on the balloon. D They act on different objects.

a. What does Newton's first law of motion state? b. Why is Newton's first law of motion sometimes called the law of inertia? c. Use what you know about inertia to explain why you feel pressed back into the seat of a car when it accelerates.