Module 3 Chapter 5 Newton's Laws of Motion

Question 1

What is Newton’s first law?

Answer 1

A body will remain at rest or continue to move at a constant velocity until an external force acts on it.

Question 2

What is Newton’s second law?

Answer 2

The resultant force on an object is proportional to the rate of change of momentum of the object, and the momentum change takes place in the direction of the force.

Question 3

What is Newton’s third law?

Answer 3

If object A exerts a force on object B, then object B will exert an equal and opposite force on object A.

Question 4

What is the relationship between force, mass and acceleration?

Answer 4

F = m*a
m = F/a
a = F/m

Question 5

Why is a book resting on a table an example of Newton’s first law and not his third?

Answer 5

Because even though there are two equal forces acting in opposite directions, they are both acting on the book. Furthermore, the forces are not of the same type; one is gravitational while the other is reactionary. A swimmer kicking off the wall of a swimming pool would be a good example of Newton’s third law.

Question 6

What is momentum?

Answer 6

mass * velocity

Momentum is a vector quantity and has the unit kg m s-1.

Question 7

What can be said of momentum in any collision or interaction?

Answer 7

It is conserved, provided there are no external forces present.

Question 8

What quantities are closely related to momentum?

Answer 8

• Mass
• Velocity
• Force
• Impulse
• Kinetic energy

Question 9

Define the principle of the conservation of momentum.

Answer 9

The conservation of momentum means that the total momentum (across all objects involved) before a collision or interaction is always equal to the total momentum after the collision or interaction, provided that no external forces such as air resistance are involved.