Question

The velocity of a motor cycle increases by an acceleration of 2ms-2 and becomes 20ms-1 in 5 sec find the initial velocity of a car

Answer 1

Answer:

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

Explanation:

Answer 2

Answer:

YOUR ANSWER WILL BE 10M/S .

Explanation:

Given :

v = 20m/s

a = 2m/s^2

t = 5s

u = ?

to find initial velocity ( u ) , applying the 1st eqation of law of motion :-

v = u + at

- v - u = at

20m/s - u = 2m/s^2 * 5s

20m/s - u = 10m/s

- u = 10m/s - 20m/s

-u = -10m/s

u = 10m/s

hence , the initial velocity of a car will be 10m/s .