Momentum, impulse and energy

Question 1

What is impulse?

Answer 1

Force x time
Measured in Ns
Impulse = mv - mu
(Change in momentum)

Question 2

How do we calculate impulse?

Answer 2

Split each time step into a trapezium and work out its area
dt (h1 + h2)/ 2
Sum over time gives you net impulse

Question 3

What is zero impulse?

Answer 3

When the positive and negative impulse are the same there is no change momentum or velocity

Question 4

What is positive impulse?

Answer 4

When the positive impulse is greater that the negative impulse so we have increased acceleration and increased momentum

Question 5

How do we work out the change in velocity?

Answer 5

Impulse / mass

Question 6

What is the equation to find ma?

Answer 6

GRF- BW = ma

Question 7

How do we find the net vertical impulse?

Answer 7

Net impulse is the sum of the 2 areas above and below 0
∫Fz - ∫BW

Question 8

What is energy?

Answer 8

(J)- Energy is the quantitative property that must be transferred to a body or system to do work

Question 9

What is the definition of 1 joule?

Answer 9

The energy required to accelerate a Kg mass at 1 m/s2 through a distance of 1m

Question 10

Was it mechanical energy split into?

Answer 10

Potential and kinetic

Question 11

What is potential energy?

Answer 11

The energy that a body possesses due to its position relative to the earth’s surface
PE= mgh

Question 12

What is kinetic energy?

Answer 12

This is the energy an object has due to its movement
KE= 1/2 mv2
If energy is conserved change in PE = change in KE