Question

A body moving along a straight line at 20 m/sec undergoes an acceleration of -4 m/sec square. After 2 seconds its speed will be- *
-8 m/sec
12 m/sec
16 m/sec
28 m/sec

Answer 1

Answer:

12 m/s

Explanation:

Given that,

u = 20m/s  ,  a = -4m/s²  ,  t = 2s  ,  v = ?

we know that,  v = u + at     ( first equation of motion )

by substituting the values , we get,

v = 20 + -4 x 2

v = 20 - 8

or, v = 12 m/s