Question

7th grade science review packet
newtons laws of motion & motion concepts
part a - multiple choice (15 questions)

1. newtons first law of motion is also called the law of: a) gravity b) momentum c) inertia d) acceleration
2. an object in motion stays in motion unless acted on by a(n): a) balanced force b) unbalanced force c) net zero force d) momentum
3. which law explains why you feel pushed back into your seat when a car accelerates? a) first law b) second law c) third law d) law of gravity
4. newtons second law relates force, mass, and: a) inertia b) friction c) acceleration d) velocity
5. the unit of force is the: a) joule b) newton c) watt d) kilogram
6. a soccer ball is kicked and starts rolling across the grass. what eventually stops it? a) inertia b) friction c) momentum d) net force
7. which of the following is an example of newtons third law? a) a rocket launches into space b) a ball sits on a table c) a book slides until it stops d) a car speeds up
8. speed is calculated by: a) distance × time b) distance ÷ time c) mass ÷ force d) force × distance
9. velocity is speed in a given: a) force b) direction c) time d) distance
10. the push or pull on an object is called: a) speed b) force c) momentum d) acceleration
11. what is the net force if 10 n acts to the right and 4 n acts to the left? a) 6 n left b) 14 n right c) 6 n right d) 0 n
12. the tendency of objects to resist a change in motion is:

Explanation:

1. Newton's First Law is the law of inertia, which states an object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force.
2. An object in motion stays in motion unless an unbalanced force acts on it, as per Newton's First Law.
3. When a car accelerates, you feel pushed back due to Newton's Second Law ($F = ma$), where the force of the car's acceleration acts on you.
4. Newton's Second Law is $F=ma$, relating force, mass, and acceleration.
5. The unit of force is the Newton.
6. Friction between the soccer - ball and the grass eventually stops the ball.
7. A rocket launching into space is an example of Newton's Third Law (action - reaction pairs).
8. Speed is calculated as distance divided by time ($v=\frac{d}{t}$).
9. Velocity is speed in a given direction.
10. The push or pull on an object is called force.
11. To find the net force, subtract the smaller force from the larger one when they act in opposite directions. So, $10N - 4N=6N$ to the right.
12. The tendency of objects to resist a change in motion is inertia.

Answer:

1. c) Inertia
2. b) Unbalanced force
3. b) Second Law
4. c) Acceleration
5. b) Newton
6. b) Friction
7. a) A rocket launches into space
8. b) Distance $\div$ Time
9. b) Direction
10. b) Force
11. c) 6 N right
12. Inertia