Newbie needs muchos help (thanks)

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A newbie seeks help with a physics problem involving a steel hammer's bounce height of 400mm after falling. The user is confused about calculating the initial velocity after the bounce and determining the times the hammer reaches a height of 300mm. Forum members suggest using kinematic equations, assuming a perfectly elastic collision for the post-bounce calculations. They encourage the user to list relevant equations and attempt to solve the problem step-by-step. The discussion emphasizes the importance of understanding the concepts of energy and motion in this context.
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newbie needs muchos help!(thanks)

right so i am new to the forums and am really glad i found them.any way just doing some revision and have come across this and i am stumped.

Q:In a particular type of hardness test a steel hammer is allowed to fall on a material being tested.If the hammer bounces to a height of 400mm determine:

a) The initial velocity immediately after bouncing on the specimen, and

b) The times when the hammer is at a height of 300mm.

take g= 9.8m/s/s

now i am stumped to find the initial velocity as in my mind i don't have enough information to fill an equation.

please help this is killing me!

(this is probably really easy but i am a newbie and need the help)

thanks in advance
 
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The initial velocity of the hammer will be the same as the final velocity of the hammer right before it hits. (unless you are accounting for lost energy when it hits)
 


mk1tt16v said:
right so i am new to the forums and am really glad i found them.any way just doing some revision and have come across this and i am stumped.

Q:In a particular type of hardness test a steel hammer is allowed to fall on a material being tested.If the hammer bounces to a height of 400mm determine:

a) The initial velocity immediately after bouncing on the specimen, and

b) The times when the hammer is at a height of 300mm.

take g= 9.8m/s/s

now i am stumped to find the initial velocity as in my mind i don't have enough information to fill an equation.

please help this is killing me!

(this is probably really easy but i am a newbie and need the help)

thanks in advance

Welcome to the PF. I'm not sure about the before-bounce part (unless they are assuming a perfectly elastic collision with no energy lost in the bounce), but after the bounce is easy. Just use the standard kinematic equations for distance and velocity with gravity being the acceleration factor.

Can you list the equations for us, and start to try to use them to solve the post-bounce part?
 

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