Mechanics

Question 1

On a velocity-time graph what does the area under the graph represent

Answer 1

Displacement/m

Question 2

On a velocity time graph what line gradient represents acceleration when velocity is positive or negative

Answer 2

Any line with a gradient deviating from v=0 (When v is positive so is gradient, when v is negative so is gradient)

Question 3

On a velocity time graph what line gradient represents deceleration

Answer 3

Any line with a gradient nearing v=0 (when v is positive gradient is negative, when v is negative gradient is positive)

Question 4

State Newtons First Law (N1L)

Answer 4

An object remains at rest or at constant velocity when when resultant force on it is 0 unless there is an external resultant force acts upon it, causing it to accelerate.

Question 5

State Newtons Second Law (N2L)

Answer 5

Force is directly proportional to the rate of change of momentum and acts in the same direction

Question 6

State Newtons Third Law (N3L)

Answer 6

When object A exerts a force on object B, object B exerts an equal reaction force of equal magnitude, opposite direction and same type of force upon object A

Question 7

Use Newton’s third law to explain why a ball bounces

Answer 7

• Only the upward contact force and downward weight of the ball act upon the ball.
• The ball pushes the ground with a force greater than weight
• The force of the floor pushing the ball up is greater than the balls weight due to N3L
• This means that the ball accelerates upwards

Question 8

Describe the 2 necessary criteria for an object to be in equilibrium

Answer 8

• No Resultant Force
• No Resultant Moment (Anti-clockwise moment = Clockwise moment)

Question 9

State the equation for work done using displacement and the condition required for it to be considered work done and not a moment

Answer 9

Work Done = Force x displacement (Only when force and displacement act parallel in the same direction)

Question 10

State the equation for work done in a spring

Answer 10

Work done = 1/2 x Force x extension

Question 11

State the equation for work done by gravity

Answer 11

Work done = mass x gravitational field strength x height

Question 12

Define Momentum

Answer 12

How easy/difficult it is to change a certain objects velocity

Question 13

State the equation for momentum

Answer 13

Momentum = mass x velocity

Question 14

State how momentum is conserved

Answer 14

In any interaction (Collisions or explosions) the momentum before the collision is the same after the collision

Question 15

Define what an impulse is

Answer 15

The change in an objects momentum

Question 16

What is the equation given to an Impulse

Answer 16

Impulse (Change in momentum) = Force x change in time

Question 17

During an elastic collision what 2 values are conserved

Answer 17

Kinetic Energy, Momentum

Question 18

During an inelastic collision what value is conserved

Answer 18

Momentum

Question 19

During an inelastic collision what value is not conserved

Answer 19

Kinetic energy

Question 20

What is the difference between a fully inelastic and partially Inelastic collision

Answer 20

Fully Inelastic - Bodies Stick Together
Partially Inelastic - Bodies do not stick together

Question 21

What is the equation for a moment

Answer 21

Moment = Force x Perpendicular Distance From Pivot to The Line of Action (Force)

Question 22

Define the principle of moments

Answer 22

An objects will remain in equilibrium when the sum of the anticlockwise moment is equal to the sum of the clockwise moment