Question

a body moving along a straight line at 20m/s undergoes an acceleration of -4m/ssquare . after 2 secs its speed will be




only answer needed

Answer 1

Given,

Initial velocity (u) = 20 m/s

Final velocity (v) = ?

Acceleration due to gravity (a) = 4 m/s²

Time (t) = 2 sec

From First Equation of Motion:

v = u + at

v = 20 + 4 * 2

v = 20 + 8

v = 28 m/s

And we know,

Velocity = displacement / time

i.e v = d / t

28 = d / 2

d = 28 * 2

d = 56 m

Answer 2

Answer:

u= 2om/s

a=-4m/s^2

t=2 sec

v=?

a=v/t-u/t

-4 = v/2 - 20/2

-4 = v/2 - 10

-4 + 10 = v/2

6= v/2

v= 12m/s

after 2 seconds the speed will be 12m/s