Ch8 Newtons Laws Of Motion

Question 1

State Newton’s Second Law

Answer 1

F=ma

Question 2

State Newton’s First law

Answer 2

Objects remain at rest or move with constant velocity unless acted on by a force.

Question 3

In a lift, downward acceleration is equal to …

Answer 3

Upward deceleration

Question 4

Define inertia

Answer 4

The mass of an object is a measure of it’s inertia, it’s resistance to change of motion.

Question 5

Define terminal velocity

Answer 5

The drag force is equal and opposite to motive force, so it moves at a constant velocity. As speed increases, drag forces increase.

Question 6

When does a falling object reach terminal velocity?

Answer 6

When drag force is equal to the weight

Question 7

Define braking distance.
Equation?

Answer 7

Distance travelled by a car in the time it takes to stop safely from when the brakes are first applied.
s=-u/2a

Question 8

Define thinking distance.
Equation?

Answer 8

Distance travelled by a vehicle in time it takes driver to react. Thinking distance=v×t0 where v=speed and t0=reaction time

Question 9

Impact force=?
Reducing impact time means ….

Answer 9

change in kinetic energy / increasing impact force.
Increasing impact time