# PHYSICS

A 75 kg box starts from the top of a ramp at point A. The coeff of fric. between surface & box is 0.275. The avg. normal force of the surface on the box (while it is on the ramp) is 3/4 of its weight.

A) What is the velocity of the box right before it hits the spring at point B?

B.) If the spring constant is 400 N/m, how far will it compress the spring?

C.) What minimum velocity must the box have at point A in order to ensure it will make the entire way back up the ramp.

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1. How far is it along the ramp from A to the spring at B?

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2. R=25
This is from Point A with a curve going to the right (if that makes any sense) .The ramp is 30 m.

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posted by T.
3. net force=mass*acceleration
1/4*mg-3/4*mu*mg=m*acceleration
knowing acceleration..
vf^2=2*a*distance
solve for vf

1/2 m vf^2=1/2 k x solve for x, the distance the spring is compressed. I can't tell, but I assume no friction the last five meters, if there is, you have to figure that in.

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