# Physics Lab

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We have a metal ball and a ramp that we can clamp to the edge of a table. We are supposed to find the coefficient of friction between the ball and the ramp. We think we should use projectile motion and the law of conservation of energy. We don't know what to do with them however because we are not allowed to use timers. How should we do this?

• Physics Lab -

Can you vary the ramp? If so, start horizontal,and see at what angle the ball starts to roll.

• Physics Lab -

no, its a metal ramp, and only works one way. Its straight most of the way at an angle of about 37 degrees, and at the bottom, it curves and is parallel to the table so that the ball will fly off the edge.

• Physics Lab -

ok,easy then.

find where it strikes the ground. Measure the height of the table, the height above the table at the top of the ramp,and the distance horizontal it traveled from the table edge.

Look at energy first:

Initial PE above table-friction*ramplength=1/2 mv^2 at launch.

now look at the air ball.
horizontaldistance=v*time
vertical drop>> t= sqrt (2g*table height).

Ok, work back to find frictionforce.