Please show all work and formulas used 1) A hammer thrower releases the hammer a

Question

Please show all work and formulas used

1) A hammer thrower releases the hammer after reaching an angular velocity of 14.2rad/s.  If the hammer is 1.55m from the shoulder joint, what is the linear velocity at release?

2) A crate of mass 45.0kg is being transported on a flatbed of a pickup truck. The coefficient of static friction between the crate and the trucks flatbead is 0.40.  The truck drives along at a constant speed until the driver sees a red light ahead.  What is the maximum (negative) acceleration the truck can have as it brakes without the crate sliding?

3) A 0.0078kg bullet moving at 575m/s penetrates a tree trunk to a depth of 0.055m.  Use work and energy considerations to find the average frictional force that stops the bullet.

Explanation / Answer

1) v = w r= 14.2*1.55=22.01 m/s

2) F = ma

friction = u mg = ma

a = u g = 0.4*9.81=3.924 m/s^2

3) W = Fd and W = 1/2 mv^2

F = 0.5*0.0078*575^2/0.055=23444 N

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