Question

multiple choice questions: circle the correct answer from the choices for each question.

1. what does newtons third law of motion state?

a) objects in motion stay in motion
b) every force has an equal and opposite force
c) force equals mass times acceleration
d) gravity pulls objects toward earth

1. when you press your hand against the wall, what happens?

a) only your hand feels the force
b) the wall does not react
c) the wall disappears
d) the wall pushes back with an equal force

1. why does a rocket move forward in space?

a) gravity pulls it forward
b) it pushes gas out the back, and the gas pushes the rocket forward
c) it floats naturally
d) the rocket pulls on the earth

1. if you stand on the ground, what keeps you from falling through earth?

a) the air supports you
b) the ground pushes up with an equal force to your weight
c) gravity stops working
d) your shoes are sticky

1. which of the following is an example of newtons third law?

a) a ball rolling down a hill
b) pushing off the ground to jump
c) water boiling
d) ice melting

Explanation:

• Question 1: Newton's third law states that for every action, there is an equal and opposite reaction. Option b is Newton's first law (inertia), option c is Newton's second law (\(F = ma\)), and option d is about gravity.
• Question 2: When you press your hand against the wall, according to Newton's third law, the wall pushes back with an equal force. Options a, b, and c violate the principle of action - reaction.
• Question 3: A rocket moves forward in space because it pushes gas out the back (action), and the gas pushes the rocket forward (reaction). Gravity in space (for a rocket far from large celestial bodies) is not the main factor (option a is wrong), floating naturally (option c) and pulling on the Earth (option d) do not explain rocket motion.
• Question 4: When you stand on the ground, the ground pushes up with an equal force to your weight (normal force). Air support (option a) is negligible in this context, gravity doesn't stop working (option c), and sticky shoes (option d) are not the physical principle at work.
• Question 5: Pushing off the ground to jump involves an action (pushing down on the ground) and a reaction (the ground pushing up on you). A ball rolling down a hill (option a) is due to gravity and Newton's second law, water boiling (option c) and ice melting (option d) are phase - change processes not related to Newton's third law.

Answer:

1. b. Every force has an equal and opposite force
2. d. The wall pushes back with an equal force
3. b. It pushes gas out the back, and the gas pushes the rocket forward
4. b. The ground pushes up with an equal force to your weight
5. b. Pushing off the ground to jump