How do i find the average velocity, the final velocity, and the acceleration of an object moving?

Question

The question goes:

A body with initial velocity of 8 meters per second moves along a straight line with constant acceleration and travels 640 meters in 40 seconds. For the 40 seconds interval: find the average velocity, find the final velocity, and the acceleration...

a clear answer would be very helpful ^ ^

Thanks....

Answer 1

Given:

Vi = initial velocity = 8 m/s

a = acceleration is constant

d = 640 m, displacement

t = 40 s, time elapse

Find:  For the 40 sec interval, find:

a)  Vavg = average velocity

b)  Vf = final velocity

c)  a = acceleration

Solution:

d = Vit + (1/2)at^2

640 = 8(40) + (1/2)(a)(40)^2

a =  2[640 - 8(40)]/(40)^2

a = 0.4 m/s^2 , acceleration    ANSWER

Vf = Vi + at

Vf = 8 + 0.4(40)

Vf = 24 m/s, final velocity     ANSWER

Vavg = (Vi + Vf)/2

Vavg = (8 + 24)/2

Vavg = 30/2

Vavg = 15 m/s, average velocity     ANSWER

Hope this helps.

teddy boy