Question

A driver of a car P traveling at 52kmph applies brakes and accelerates uniformly to stop the car in 5s. The driver of another car Q traveling at 34kmph also applies brakes and slowly stops the car in 10s. Which car has undergone a greater acceleration?

Answer 1

Answer:P

explanation:

For P

taking initial velocity u=52kmph

final velocity v=0kmph (car stops)

time=5sec

=5/3600hours

acceleration

(v-u)/t

(0-52)/(5/3600)

-52(3600)/5

-37440m/s^2

For Q

initial velocity u=34kmph

final velocity v=0kmph

time=10 sec

=10/3600 h

acceleration

(v-u)/t

(0-34)/(10/3600)

-34/(10/3600)

-34(3600)/10

-12240m/s^2

Negative sign denotes retardation

magnitude is More in case of P

so answer is P