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.

a = 2 m/s²

v₄ = 8 m/s

Explanation:

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

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:

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):

v₄ = 8 m/s

answer: 2×10^-2kg

explanation: density= mass per volume

vol=mass/density

converting to s.i units we have;

3÷1000kg = 0.003

1.5÷100m = 0.15

0.003/0.15 = 0.02kg