Question

Under the influence of a force, an object of mass 4 kg

accelerates from 3 m/s to 6 m/s in 8 s. How much work
was done on the object during this time?

Answer 1

53.3J

Step-by-step explanation:

Given parameters:

Mass of object = 4kg

Initial velocity = 3m/s

Final velocity = 6m/s

time taken = 8s

Unknown:

Amount of work done on body = ?

Solution:

Work done is the force applied to move a body through a particular distance.

Work done = force x distance

let us find force and distance:

Using newton's second law of motion:

F = ma

where m is the mass and a is the acceleration

First find the acceleration;

Acceleration =
`(V- u)/(t)`

V is the initial velocity

U is the final velocity

Input the parameters;

a =
`(6-3)/(8)` = 0.38m/s²

F = 4 x 0.38 = 1.5N

To find the distance;

V² = U² + 2as

where s is the distance

6² = 3² + 2(0.38)s

s = 35.5m

Work done = 1.5 x 35.5 = 53.3J