momentum momentum is the amount of ‘oomph’ a moving object has
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Momentum Momentum is the amount of ‘oomph’ a moving object has. “The more ‘oomph’ the object has, the harder it is to stop” p = mv (vector quantity) p = momentum (measured in ________) m = mass (in kg) v = velocity (in ms -1 ). Question Why do we need to wear seat belts?. Example ONE - PowerPoint PPT PresentationTRANSCRIPT
MomentumMomentum is the amount of ‘oomph’ a moving object has.“The more ‘oomph’ the object has, the harder it is to stop”
p = mv (vector quantity)
p = momentum (measured in ________)m = mass (in kg)v = velocity (in ms-1)
QuestionWhy do we need to wear seat belts?
Example ONEA cricket ball of mass 500 g is bowled straight into the batter’s face at a speed of 35 ms-1. The batter blocks the ball with his bat, then the ball flies directly back towards the bowler’s face at 25 ms-1.a) Calculate the ball’s initial momentumb) Calculate the ball’s final momentumc) Calculate the ball’s change in
momentum
Example TWOA 120 kg man accidently falls off the roof of a building. The man’s velocity, the moment before he hits the ground, is 40 ms-1. He comes to a complete stop after he has hit the ground.Calculate his change in momentum.
QuestionDo you think the man survived the fall?
Impulse = “change in momentum”Δp = pf – pi
= mvf – mvi
= m (vf – vi) = m Δv = m a Δt = F Δt
F = ma
a = ΔvΔt
Impulse = “change in momentum”
Δp = F Δt“Change in momentum
is a result of force”
QuestionDo you think the man survived the fall?
QuestionHow do air bags work?
Example THREEA driver tries to slow down a runaway car by pushing against its motion. The car’s mass is 2100 kg and its initial velocity is 3.0 ms-1. Will the driver manage to stop the car if:• the resultant force on the car is 600 N
(against the car’s motion) and;• the force is applied for 9.0 seconds?
• Activity 10A (green book, pg. 123) Questions 1, 2, 3 and 6 only