A car is moving along a straight road with a uniform acceleration. It passes through two points P and Q separated by a distance with velocity `30km//h` and `40 km//h` respectively. The velocity of the car midway between P and Q is

Options

A. 33.3km /h
B. `20 sqrt2 km//h`
C. `25 sqrt2 km//h`
D. 35km/h

Answer

C

Explanation

Let PQ=x, then
`a = (40^(2) - 30^(2))/(2x)= (250)/(x) [ :. V^(2) = u^(2) + 2as]` Also, velocity at mid point is given by
`v^(2) -30^(2) = 2 xx (350)/(x) xx (x)/(2)`
This gives `v= 25 sqrt2km//h`