- #1

jsmith613

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**Kinematics -- marbles rolling down a ramp and into sand**

## Homework Statement

14) The student carries out an experiment to investigate momentum and collisions. A ball bearing is rolled down a ramp clamped at the edge of a bench. The ball bearing makes a head-on collision with a marble at the bottom of the ramp.

The ball bearing and the marble both move forward in the initial direction of the ball bearing after the collision, landing in a tray containing a layer of sand.

(a) Initially the ball bearing rolls down the ramp without the marble in a place. The ball bearing falls a verticle distance of 1.2m and lands a horizontal distance 95cm forward of the end of the ramp. Show that the speed of the ball bearing leaving the ramp is about 2ms

^{-1}

**I worked this out, CORRECTLY as 1.9 ms**

^{-1}(b) When the ball bearing is rolled down the ramp with the marble in place, it knocks the marble forwards. The ball bearing lands a horizontal distance 64cm forward of the end of the ramp, and the marble lands a further 93cm forward from this position. Calculate the ratio of masses of the ball bearing and he marble

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PART (b) IS THE QUESTION ON WHICH I AM STUCK

## Homework Equations

v

^{2}= u

^{2}+ 2as

## The Attempt at a Solution

so

m

_{1}u

_{1}+ m

_{2}u

_{2}= m

_{1}v

_{1}+ m

_{2}v

_{2}

m

_{1}u

_{1}= 1.9m

_{1}

m

_{2}u

_{2}= 0

1.9m

_{1}= m

_{1}v

_{1}+ m

_{2}v

_{2}

BUT I cannot find v

_{1}OR v

_{2}as I don't know the distance the balls FALL