Distance after breaking work ?

1 Answer
Mar 5, 2017

Both cover the same distance.

Explanation:

Let p = m_1 v_1 = m_2 v_2p=m1v1=m2v2 be the momentum attached to car and lorry.

The work needed to attain rest is in each case

The momentum m vmv has associated a mechanical energy given by 1/2mv^212mv2. Also ff is the resistive force the same for both cars and ww is the dissipated mechanical energy, as breaking work.

1/2m_1v_1^2=w_1 = f d_112m1v21=w1=fd1 and
1/2m_2v_2^2=w_1 = f d_212m2v22=w1=fd2

Here d_1,d_2d1,d2 are the distances covered until rest. Dividing term to term

(m_1v_1^2)/(m_2v_2^2)=d_1/d_2m1v21m2v22=d1d2

but m_1 v_1 = m_2 v_2m1v1=m2v2 so d_1/d_2=1d1d2=1 hence d_1=d_2d1=d2