Motion

Question 1

Define the term centre of gravity

Answer 1

The point which the weigh of a body may be considered to act

Question 2

In projectile motion the horizontal component is

Answer 2

Constant

Question 3

What does derived mean

Answer 3

A result of a mathematical combination

Question 4

Using newtons laws of motion explain the motion of the spheres during the collision in terms of the forces acting on them

Answer 4

Sphere A applies force to sphere B.
According to N3 sphere B will apply an equal + opposite force to sphere A
This causing sphere A to decelerate and stop.
Since the impulse acting on the spheres is equal sphere B will have the same energy and speed as sphere A.

Question 5

Explain how bending both knees when landing helps the gymnast prevent injury

Answer 5

Time to come to rest is greater, so rate of change of momentum is less, therefore there is less change of rate in force