Newton’s Laws Concept Questions
#1-6 Answer True or False and explain your answer or give an example proving the statement true or false.
1.
It is possible to have motion in the absence of a force.
2. If an object isn’t moving, no external force acts on it.
3. If a single force acts on an object, the object accelerates.
4. If an object is accelerating, a force is acting on it.
5. If an object isn’t accelerating, no external force is acting on it.
6. If the net force acting on an object is in the positive x-direction, the object moves only in the positive x-direction.
7. A small sports car collides head on with a massive truck.
a. Which vehicle will experience the greatest magnitude force: the car, the truck, or neither? Explain.
b. Which will undergo the greater magnitude acceleration?
8. When throwing a baseball, a force is exerted by the hand on the ball.
a. Is this force a field force or a contact force?
b. Throwing a ball 6 m straight upwards requires a 25 N throwing force. How strong is the throwing force it
experiences when the ball is half way to the top? At the very top? Half way back downwards?
9. A space explorer is moving through space far from any planet or star. He notices a large rock, taken as a
specimen from an alien planet, floating around the cabin. Should he push it gently or kick it toward the storage
compartment? Why?
10. Identify the action reaction pairs in the following situations:
a. A snowball hits a girl in the back.
b. A baseball player catches a ball.
c. A man takes a step.
d. A gust of wind strikes a window.
11. A truck loaded with sand accelerates along a highway. If the driving force stays the same on the truck, what
happens to the truck’s acceleration if its trailer leaks sand at a constant rate through a hole in the bottom?
12. A passenger sitting in the rear of a bus claims that she was injured as the driver slammed on the brakes. She
claims that the rapid braking caused a suitcase to come flying towards her from the front of the bus. If you were
a judge in this case, how would you rule and why?
13. Tiger Woods can hit a golf ball with 55 N of force. How hard does the ball hit back on the club? (a) more than 55
N of force, (b) less than 55 N of force, (c) exactly 55 N of force. Explain
14. What action reaction pair is responsible for pushing a car forward?
15. A rubber ball is dropped to the floor. What force causes the ball to bounce? Does the Earth “bounce” too?
16. While rummaging in her backpack for her cell phone, Sally’s Mini-Cooper rear ends Joey’s Suburban. Sally’s car is
totaled while the suburban is fine. If Sally’s car hit the suburban with 30 N of force, how much force did Joey’s
car exert on Sally’s? (a) more than 30 N, (b) less than 30 N, (c) exactly 30 N.
17. Helpful Henry’s car is pushing Flat-tire Fred’s car to the car shop. While the cars are accelerating up to 15
miles/hour Helpful Henry needs to push Fred’s car with 60 N of force. With what force does Flat-tire Fred’s car
push on Helpful Henry’s car?
18. An army plane wants to drop supplies to a group of physics students stranded on an island. In order for the
package to land on the island, the pilot needs to drop the package before the plane is directly above the island.
Explain why using Newton’s Laws (you may ignore air resistance).