Paper 2 - Forces and Motion

Question 1

What is the equation for momentum?

Answer 1

p=mv

Question 2

Use the idea of momentum to explain safety features

Answer 2

• Change in momentum is the same with or without an airbag.
• Airbags and crumple zones in cars are used to increase the period of time that the collision takes to reduce the force of the impact
• Reduces rate of change of momentum

Question 3

Equation for force in terms of momentum

Answer 3

force=change in momentum / time taken

F=(mv-mu) / t

Question 4

What is Newton’s third law?

Answer 4

For every action (force) in nature, there is an equal and opposite reaction

Question 5

What is the equation for the moment of a force?

Answer 5

moment=force x perpendicular distance from the pivot point

M=Fd

Question 6

How does the weight of a body act?

Answer 6

The weight of a body acts through it’s centre of gravity

Question 7

What is the principle of conservation of momentum?

Answer 7

total momentum before collision = total momentum after collision

as long as there are no external forces acting

Question 8

How is an oscilloscope used to measure the time period of a wave?

Answer 8

• Freezing the screen
• To count number of squares in a full cycle
• Then multiply number of squares for full cycle by time base