Question

practice: application of motion laws
part 1 name that law: read each scenario below and name which law is at work. choose from: newtons 1st law, newtons 2nd law, newtons 3rd law, the law of universal gravitation, and the law of conservation of momentum.

1. your dirty clothes, left on the floor overnight, are there when you wake up in the morning. - n(1st)l
2. jumping on a trampoline causes you to fly up in the air.
3. a kicked soccer ball will eventually stop rolling due to the grass.
4. a motorcycle can reach a speed of 60 mi/hr much faster than a minivan.
5. when a fireman turns on the water coming through the hose he feels the hose push him backwards. sometimes it takes more than one fireman to hold the hose.
6. a driver isnt paying attention while he texts and drives, colliding with the parked car in front of him and transferring all of his cars motion force into it.
7. you run into your friend while ice - skating and both of you fall in opposite directions.
8. the bike you are riding hits a crack in the sidewalk and stops quickly, sending you flying over the handlebars.
9. if you dont keep giving a car gas, the car will eventually stop.
10. a baseball player hits a ball towards the outfield.
11. a satellite in orbit maintains a constant speed while orbiting around the earth.
12. an acorn falls from a tree and lands on the ground.
13. in a head - on collision, if you arent wearing your seatbelt you could go through the window.
14. it takes an airplane nearly 3/4 of a mile to stop.
15. swimming in a pool requires that you push back on the water in order to go forward.

part 2 predict the motion: read and predict the motion of the object, based on which law is at work.

1. according to newtons 1st law of motion, if you leave a cookie on a plate and there is no one else in the house, where will the cookie be in an hour?
2. according to newtons 2nd law of motion, if you hit a ping - pong ball and a tennis ball with a tennis racket, which one should have a greater acceleration?
3. according to newtons 3rd law of motion, if you apply the force of your body down onto a trampoline, what should the trampoline do back to you?
4. according to the law of universal gravitation, if you drop a tennis ball and an apple at the same time, what should you observe?
5. according to the law of conservation of momentum, if you are playing pool and hit the cue ball at the stationary 8 - ball, what should happen?

Explanation:

1. Newton's 1st Law: Objects at rest stay at rest. Dirty clothes remain on the floor as no external force acts on them.
2. Newton's 3rd Law: Jumping on trampoline - for every action (pushing down), there is an equal and opposite reaction (flying up).
3. Newton's 1st Law: Soccer ball stops due to friction (external force), changing its motion.
4. Newton's 2nd Law: Motorcycle accelerates faster as it has less mass for the same force compared to minivan ($F = ma$).
5. Newton's 3rd Law: Fireman feels hose push back as water comes out - action - reaction pair.
6. Law of Conservation of Momentum: Driver's car collides, momentum is transferred.
7. Newton's 3rd Law: Running into friend on ice - equal and opposite forces make you fall in opposite directions.
8. Newton's 1st Law: Bike stops, rider continues moving forward due to inertia.
9. Newton's 1st Law: Car stops without gas as friction acts as external force.
10. Newton's 2nd Law: Bat hitting ball - force causes ball to accelerate.
11. Newton's 1st Law: Satellite has constant speed as no non - gravitational force acts tangentially.
12. Law of Universal Gravitation: Acorn falls due to gravitational pull of Earth.
13. Newton's 1st Law: In a collision, passenger without seatbelt continues moving forward due to inertia.
14. Newton's 1st Law: Airplane takes long distance to stop due to inertia and friction.
15. Newton's 3rd Law: Swimming - pushing water back causes forward motion.
16. Answer: The cookie will be in the same place on the plate as there is no external force to move it according to Newton's 1st Law.
17. Answer: The ping - pong ball will have a greater acceleration as it has less mass. According to Newton's 2nd Law ($a=\frac{F}{m}$), for the same force, a smaller mass results in a larger acceleration.
18. Answer: The trampoline should push you back up with an equal force according to Newton's 3rd Law.
19. Answer: They should hit the ground at the same time as all objects fall with the same acceleration ($g$) near the Earth's surface according to the Law of Universal Gravitation.
20. Answer: The cue ball should stop or change direction and the 8 - ball should start moving. According to the Law of Conservation of Momentum, the total momentum before the collision is transferred to the 8 - ball.

Answer:

1. Newton's 1st Law
2. Newton's 3rd Law
3. Newton's 1st Law
4. Newton's 2nd Law
5. Newton's 3rd Law
6. Law of Conservation of Momentum
7. Newton's 3rd Law
8. Newton's 1st Law
9. Newton's 1st Law
10. Newton's 2nd Law
11. Newton's 1st Law
12. Law of Universal Gravitation
13. Newton's 1st Law
14. Newton's 1st Law
15. Newton's 3rd Law
16. The cookie will be in the same place on the plate.
17. The ping - pong ball.
18. Push you back up with an equal force.
19. They should hit the ground at the same time.
20. The cue ball should stop or change direction and the 8 - ball should start moving.