Question

Pls answer correct for class 9 only

Answer 1

Answer:

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