Chapter 8 Impulse and Momentum

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1. A 0.060kg ball is propelled by a 1.10kg racquet from rest to a speed of 40.0m/s. If the two objects are in contact for 250ms, calculate the average force exerted by the racquet on the ball.(15)

2. A 60.0kg swimmer stands at the edge of a 200kg boat that is motionless on the water of a lake. If the swimmer dives from the boat in a horizontal direction due east at 8.00m/s, calculate the velocity of the boat if friction between the boat and the water is neglected.(15)

3. A 500kg car traveling due east at 54.0km/h collides head on with a 3000kg van moving at 18.0km/h. If the two vehicles stick to each other as a result of the collision, calculate the velocity of the combined mass.(15)

4. An 18.0g arrow is fired into a 3.00kg pumpkin suspended on a string. The arrow imbeds itself in the pumpkin and makes it move at 1.50m/s due east. Calculate the velocity of the arrow just before it enters the pumpkin.(15)

1)

F= M * A

A= (Vf – Vi ) / T = (40.0 m/s - 0) / (.250 s)

A=160m/s^2

F = 0.060kg * 160m/s^2 = 9.6 N

2)

P=m v

P=60* 8.00 m/s

P=480n*s

480= 200*vb

vb=480/200=2.4m/s

2.4m/s due West

3)

M1=500kg

M2=3000kg

V1=54km/h=15 m/s

V2=18.0 km/h = 5 m/s

m1v1 - m2v2 = (m1 + m2)v'

500*15 - 3000*5 = (500+3000)V

V=-7500/3500=-2.12

2.12 m/s due west

4)

m1v1 - m2v2 = (m1 + m2)v'

0.018kg*vi – 0 =3.018*1.50

Vi=4.527/0.018=251.5=252m/s

252 m/s due east