Newton’s First Law (Inertia)
What does Newton’s First Law state?
Answer: Objects stay at rest or in motion unless acted on by an unbalanced force.
What formula summarizes Newton’s Second Law?
Answer: Force = Mass × Acceleration (F = ma).
State Newton’s Third Law.
Answer: For every action, there is an equal and opposite reaction.
What is gravity?
Answer: Force of attraction between objects with mass.
What happens when forces are balanced?
Answer: No change in motion.
What happens to weight on the Moon?
Answer: Decreases; gravity is weaker.
What type of force is needed to change motion?
Answer: A net (unbalanced) force.
Two objects, same force: which accelerates more?
Answer: The one with less mass.
Bird flaps wings—what happens?
Answer: Air is pushed down, bird moves up.
How does mass affect gravity?
Answer: More mass = stronger gravity.
What happens when forces are unbalanced?
Answer: Motion changes.
Heavier vs lighter in vacuum—who falls faster?
Answer: Same rate (no air resistance).
Example of First Law in action?
Answer: A soccer ball stays still until kicked.
2 kg ball pushed with 10 N: acceleration?
Answer: 5 m/s².
Action–reaction when walking?
Answer: Foot pushes ground back, ground pushes foot forward.
Two factors that affect gravity strength?
Answer: Mass and distance.
Ball slows on grass—why?
Answer: Friction opposes motion.
Double distance between objects—gravity effect?
Answer: One-fourth as strong.
Why does a passenger move forward when a car stops?
Answer: Inertia keeps the passenger moving while the car stops.
How does changing mass affect acceleration?
Answer: Increasing mass decreases acceleration.
Why does a balloon fly when air escapes?
Answer: Air pushes backward; balloon moves forward.
Compare gravity of Earth vs Moon.
Answer: Earth’s is stronger due to larger mass.
Cart pushed harder moves faster—why?
Answer: Newton’s Second Law (F = ma).
Rocket launch—2 laws in action?
Answer: Third (push/pull) and Second (F=ma).
Predict what happens if an astronaut pushes a tool in space.
Answer: The tool keeps moving until acted upon by another force.
Which accelerates faster: 5kg cart with 15N or 3kg with 15N?
Answer: 3 kg cart.
Two skaters push off—what happens?
Answer: Both move opposite directions with equal force.
Effect of distance on gravity?
Answer: Greater distance = weaker gravity.
Equal forces opposite directions—result?
Answer: Forces cancel; no motion change.
Doubling mass vs halving distance—bigger effect?
Answer: Halving distance.