Let the initial velocity be V0
For (7), we have an automobile with V0 = 15 m/s, then it accelerating 2 m/s^2, which mean the speed is increasing by 2 m/s for every second.
So, in 1 second, the velocity will be (15 + 2) = 15 + 1*2= 17 m/s
in 2 seconds, it'll be (15 + 2 + 2) = 15 + 2*2 = 19 m/s
in 3 seconds, it'll be (15 + 2 + 2 + 2) = 3*2 = 21 m/s
and so on.
Easily, we can create the formula to find the final velocity with the work above, which is:
Vt = V0 + t*a, with Vn as final velocity, a as acceleration, and t as time
So,
V10 = 15 + 10*2 = 15 + 20 = 35 m/s
(8) had similar problem. But instead of finding the final velocity, you need to find the acceleration. Try it yourself
