(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

A car of mass 1.2 tonnes collides with a stationary van of mass 2.4 tonnes. After the collision the two vehicles become entangled and skid 15 m before stopping. Police accident investigators estimate that the magnitude of the friction force during the skid was 2880 N. Assume the road is horizontal and that all the motion takes place in a straight line.

a) Find the speed of the vehicles just after the collision.

b) Find the speed of the car before the collision.

2. Relevant equations

[tex]m_1u_1 + m_2u_2 = (m_1+m_2)v[/tex]

[tex]p = mv[/tex]

[tex]v^2 = u^2 + 2as[/tex]

3. The attempt at a solution

a) 1200u_{1}+ 0 = 3600v

to find out the velocity after the collision, use v as the initial velocity to travel 15m with a frictional force of 2880 N.

v^{2}= u^{2}+ 2as

[tex]0 = u^2 + 2as[/tex]

[tex]0 = u^2 + 30a[/tex]

[tex]f = ma[/tex]

[tex]f/m = a[/tex]

[tex](3600v - 2880)/3600 = a[/tex]

[tex] v - 288/360 = a[/tex]

[tex]u^2 + 30(v-288/360) = 0[/tex]

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# Homework Help: Car of Mass Momentum Question

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