Title: Mid-Unit Assessment
Course: MNPCC Physics > Section: Newton's Third Law

Use this quiz to see how your knowledge of the content is progressing.

Q: A bowling ball hits a bowling pin, which of the following is true?
- The ball will slow down more than the pin speeds up. (The ball has more mass.)
- The pin will speed up more than the ball slows down. (Correct.)
- The amount the ball slows down is equal to the amount the pin speeds up. (The ball has more mass.)
A: The pin will speed up more than the ball slows down.
If right: Your answer is correct.
If wrong: Your answer is incorrect.

Q: A horse is pulling a cart.  The forces on each are shown.  Which way will they accelerate?

Image by Pearson Scott Foresman / Public Domain
- Additional forces must be shared in order to answer this. (Correct)
- The two forces balance out so there will be no acceleration. (The forces can't cancel as they are on two different objects.)
- The cart will accelerate forwards and the horse will accelerate backwards. (They are attached and must have the same acceleration.)
A: Additional forces must be shared in order to answer this.
If right: Your answer is correct.
If wrong: Your answer is incorrect.

Q: A student sits on a chair.  What is the reaction force to the Earth pulling down on the student?
- The student pushing down on the chair. (Not the correct system.)
- The student pulling up on the chair. (Not the right system.)
- The student pushing down on the Earth. (Right objects, wrong direction.)
- The student pulling up on the Earth. (Correct.)
A: The student pulling up on the Earth.
If right: Your answer is correct.
If wrong: Your answer is incorrect.

Q: How does the force of the Earth on you compare to the force of you on the Earth.
- The force from the Earth on you and the force from you on the Earth are equal. (Correct)
- The force of the Earth on you is greater than the force of you on the Earth. (They are equal.)
- The force of the Earth on you is less than the force of you on the Earth. (They are equal.)
A: The force from the Earth on you and the force from you on the Earth are equal.
If right: Your answer is correct.
If wrong: Your answer is incorrect.

Q: A sailboat has a fan on it directly behind the sail.  Which direction should it face in order to most affect the speed of the boat?
- Toward the back of the boat. (Correct.)
- Directly into the sail. (Then you can have no external force and the air will be blown into the sail.)
- It will work equally well both ways. (The only way to have it interact with something external to the system is to have it face away from the sail.)
A: Toward the back of the boat.
If right: Your answer is correct.
If wrong: Your answer is incorrect.

Q: Which object will be harder to be brought to a stop.  A 0.2 kg ball moving at 20 m/s or a 4 kg ball moving at 2 m/s?
- It will be equally difficult to stop them both. (Their momenta are not equal.)
- The more massive ball will be more difficult to stop. (Correct.)
- The faster moving ball will be more difficult to stop. (It has less momentum.)
A: The more massive ball will be more difficult to stop.
If right: Your answer is correct.
If wrong: Your answer is incorrect.

Q: A filled balloon that is released so air comes out of the neck flies around because...
- As it pushes gas out the back, the gas pushes back on the balloon. (Correct.)
- The gas that is pushed out of the balloon pushes on the gas already present around it. (That would only move the air around, forces need to be on the balloon to accelerate the balloon.)
- The gas that is pushed out pushes against the ground/wall. (Then the force would decrease with distance from a surface, and only forces on an object (balloon) can affect that object.)
A: As it pushes gas out the back, the gas pushes back on the balloon.
If right: Your answer is correct.
If wrong: Your answer is incorrect.

Q: Two identical model rockets are being subjected to engines that have the same thrust.  In rocket A the engine burns for 10 seconds, and for rocket B the engine burns for 6 seconds.
- Rocket A (Correct)
- Rocket B (Rocket A has the force applied for more time.)
- The final speed will be identical. (Rocket A has the force applied for more time.)
A: Rocket A
If right: Your answer is correct.
If wrong: Your answer is incorrect.

Q: Two identical cars are both traveling at 30 m/s.  Car A comes to a stop in 5 seconds and Car B comes to a stop in 10 seconds.  Which requires more force to stop?
- Car A (Correct.)
- The forces are equal. (The time impacts the acceleration.)
- Car B. (The opposite is true.)
A: Car A
If right: Your answer is correct.
If wrong: Your answer is incorrect.

Q: A small piece of space debris impacts the space station.  How do their accelerations compare?
- The debris accelerates more. (Correct.)
- The accelerations are equal. (The forces are equal, but the masses are different.)
- The space station accelerates more. (Acceleration is inversely proportional to mass. And force is the same.)
A: The debris accelerates more.
If right: Your answer is correct.
If wrong: Your answer is incorrect.