A certain force exerted for `1.2s` raises the speed of an object from `1.8m//s` to `4.2m//s`. Later, the same force is applied for `2 seconds`. How much does the speed change in `2s`?

Explanation

Here, `t=1.2s, u=1.8m//s, v= 4.2m//s`
acceleration, `a =(v-u)/t = (4.2-1.8)/(1.2)=(2.4)/(1.2)= 2m//s^(2)`
Now, aas force applied is the same, it will produce the same acceleration.
Change in speed=accelerationxxtime for which force is applied `=2xx2= 4m//s`