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1)A crowbar is at an angle of 30 degrees from horizontal. If a force of 40N is a

ID: 1622036 • Letter: 1

Question

1)A crowbar is at an angle of 30 degrees from horizontal. If a force of 40N is applied straight down 0.8m from point P, what is the torque about point p?

2) A particular sligshot uses a rubber band with a spring constant of 200 N/m. If I pull the band back 0.5m from equilibrium to shoot a 30 gram projectile, how high can I shoot it (straight up)?

3) A 800g hammer is traveling at 15m/s before it hits a nail. If impact of nail causes it to come to a stop in 1.0 m/s. what is the average force exerted on the hammer by the nail? what is the kinetic energy of the hammer?

Explanation / Answer

1) torque = rfsintheta

T = 0.8*40*sin30 = 16 Nm

2) 1/2kx^2 = mgh

h = 200*0.5^2/2*0.03*9.8

h = 85.03 m

3) impulse = momentum

f*t = mv

f = 0.8*15/1

f = 12 N

k = 1/2mv^2 = 90J