Question

Travelling at an acceleration of 2 m/s2 , the velocity of a bus changes from 10 m/s to 24 m/s. For how long does it travel?

Answer 1

Explanation:

Initial speed of the car is u.

Final speed of the car v=0

Let the retardation of the car be a.

Using v

2

−u

2

=2aS

Or 0−u

2

=2aS

⟹ S∝u

2

(for same a)

Given : S=40m u

′

=2u

∴

S

S

′

=

u

2

(u

′

)

2

=2

2

Or

40

S

′

=4

⟹ S

′

=160m

Answer 2

SOLUTION :

intial velocity ( u ) = 10 m/s

final velocity ( v ) = 24 m/s

acceleration ( a ) = 2m/s²

by I equation of motion , we get

v = u + a t

24 = 10 + 2 t

2t = 24 - 10

2t = 14

t = 7 seconds