- #1

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Thank you

## Homework Statement

Two trolleys A and B, of mass 0.70kg and 0.80kg respectively, are on a horizontal track and held together by a compressed spring. When the spring is released the trolleys separate freely and A moves to the left with an initial velocity of 4.0m/s.

Calculate:

a) the initial velocity of A

b) the energy initially stored in the spring

## Homework Equations

F=ma

## The Attempt at a Solution

a) (0.70x4.0)=(0.80xV)

v=(0.70x4.0)/(0.80)

v=3.5m/s

b) This is a transfer of elastic potential energy to kinetic energy -

Energy=1/2mv^2

mv=p(momentum)

1/2(0.70x4.0)^2 + 1/2(0.80x3.5)^2

=0.0392 + 3.92

=3.9592 J