Question

An object is moving at the speed of 20m/s an acceleration of 4m/s^2 is acting opposite of the motion of the object for 15 second , draw a-t graph for entire motion

Answer 1

Explanation:

In order to answer this question, we must apply newton's first equation of motion

v = u + at

Where v is the final velocity in m/s, which is we shall attempt to find,

u is the initial velocity in m/s, given in the question as 20m/s

a is the acceleration of the body in m/s2, in the question, it is indicated to be 4m/s2

t is the time in seconds, from the question, it is 4s.

v = 20 + 4*4

v = 20 + 16 = 36m/s

As for the distance, either the second or third equation of motion can be used.

Using the second equation,

s (distance) = u*t + 0.5*a*(t^2)

s = 20*4 + 0.5*4*(4*4)

s = 80 + 32 = 112m

Using the third equation of motion,

v2 = u2 + 2as

36^2 = 20^2 + 2*4*s

1296 = 400 + 8 * s

8*s = 1296 - 400 = 896

s = 896/8 = 112m