Question

Pls answer correct
for class 9 only

Answer 1

hope it helps

Step-by-step explanation::

a) Consider a body having initial velocity 'u'. Suppose it is subjected to a uniform acceleration 'a' so that after time 't' its final velocity becomes 'v'. Now, from the definition of acceleration we know that:

Acceleration = Time taken Change in velocity or Acceleration = time taken

Final velocity- Initial velocity

So, a= t v−u

​ at=v−u and, v=u + at

where v= final velocity of the body

u= initial velocity of the body

a= acceleration

and t= time taken

(b) Initial velocity, u=54km/h=15m/s

Final velocity, v=0m/s

Time, t=8s

Acceleration, a=?

a= t v−u

​ = 8 0−15

​ = 8 −15 ​ m/s 2

=−1.875m/s 2