Unit 2.2 - Newton's Laws

Question 1

Define the term inertia and explain its relationship with mass.

Answer 1

Inertia is the resistance of an object to change its motion. Objects with greater mass have a greater inertia, so a greater resultant force is required to change their motion.

Question 2

State Newton’s first law of motion.

Answer 2

An object will remain at rest or in uniform motion in a straight line, unless acted on by an unbalanced force.

Question 3

State Newton’s second law of motion.

Answer 3

Force is equal to mass multiplied by acceleration (F=ma)

Question 4

What is the distinction between weight and mass?

Answer 4

Weight is the force of gravity acting on an object’s mass, whereas mass is a measure of the amount of matter in an object.

Question 5

Explain the concept of terminal speed.

Answer 5

When a falling object increases its speed, the air resistance acting on it increases, while the force of weight of the object stays constant - eventually, weight and air resistance are equal, so there are no unbalanced forces and the object’s speed remains constant.

Question 6

State Newton’s third law of motion.

Answer 6

If body A exerts a force on body B, then body B exerts an equal and opposite force on body A.