Question

The body starts from rest and moves evenly accelerated. At the end of the eighth second of movement, its speed is 16 m / s. Calculate the acceleration of the body and how fast it was at the end of the fourth second.

Answer 1

a = 2 m/s²

v₄ = 8 m/s

Step-by-step explanation:

We can find the final speed at the end of eight second by using first equation of motion:

`v_(f) = v_(i) + at\\`

where,

vf = final velocity at 8th second = 16 m/s

vi = initial velocity = 0 m/s

a = acceleration = ?

t = time = 8 s

Therefore, using the values in the equation we get:

`16\ m/s = 0\ m/s + a(8\ s)\\\\a = ((16\ m/s))/(8\ s)`

a = 2 m/s²

Now, we can apply same equation of motion for 4 seconds of motion to find the velocity at the end of 4th second (v₄):

`v_(4) = 0\ m/s + (2\ m/s^2)(4\ s)\\`

v₄ = 8 m/s