A car travelling at 90.0km/h is 100.0m behind a truck travelling at 50.0km/h. How many seconds will it take the car to reach the truck?

Question

Please show me how to solve using v_av = d/t.

Answer 1

v = speed of car = 90 km/h

u = speed of truck = 50 km/h

d = initial separation distance = 100 m = 0.1 km

 

They meet at time t such that

 

vt = d + ut

 

t(v - u) = d

 

t = d/(v - u) = (0.1 km) / [(90 - 50) km/h] = 0.0025 hours

 

You can convert to seconds or some other convenient units if you wish.