Newton's Laws of Motion Flashcards

Inertia is defined as:

Answer: The tendency of an object to resist changes in its state of motion

Inertia is an object's resistance to changes in motion, and it is proportional to the object's mass.

A car of mass 1,000 kg accelerates from rest to 20 m/s in 10 seconds. What is the net force on the car?

Answer: 2,000 N

a = Δv/t = 20/10 = 2 m/s²; F = ma = 1000 × 2 = 2,000 N.

If you exert a force on a skateboard and it accelerates at 2 m/s², but a heavier skateboard with the same force accelerates at 1 m/s², what does this tell you?

Answer: Acceleration decreases as mass increases

Newton's Second Law shows that for constant force, greater mass results in less acceleration (inverse relationship).

Which best describes the action-reaction pair when a bat hits a baseball?

Answer: The bat exerts force on the ball; the ball exerts an equal and opposite force on the bat

Newton's Third Law: the bat and ball exert equal and opposite forces on each other.

A spacecraft traveling in deep space (no gravity, no air resistance) turns off its engines. What happens?

Answer: It continues at constant velocity

With no net force, Newton's First Law says the spacecraft continues at constant velocity.

A 2 kg book rests on a table. The normal force from the table on the book is approximately:

Answer: 19.6 N

The normal force equals the weight: W = mg = 2 kg × 9.8 m/s² = 19.6 N.

If you push two objects with the same force but one has more mass, which object has greater inertia?

Answer: The heavier object

Inertia is directly proportional to mass; the heavier object resists changes in motion more.