Question

An automobile travelling with a speed of 60km/h can break to stop within a distance of 20m. If a car is going twice as fast, then what is the stopping distance? Answer with full procedure.

Answer 1

Answer is 20 because 60x2=120 and 20 mx2=40m

Answer 2

given u1=60km/h

s1=20m

u2=120km/h

distance(S2)=?

we can use this fomULA=(U1/U2)²=S1/S2  

 =(60/120)²=20/S2

=3600/14400 =20/S2

ON SOLVING 3600/14400 we get 1/4 =20/s2

therefore S2=20×4

=S2= 80m