Question

a box with 2 kg in mass was initiwlly moving on a smooth and stright plane at velocity of 2 m/s then on that box applied a force F=20 N so that velocity becomes 8 m/s. Determine :
A. The work done by force F
B. The distance travelled

Help please
Dibantu ya

Answer 1

Why do we fear in these types of questions? We should not..... Let's see step by step solution :

GIVEN DETAILS :-

Mass (m) = 2 kg

Initial velocity (u) = 2 m/s

Force (F) = 20 N

Final velocity (v) = 8 m/s

Acceleration (a) = ? m/s²

Distance travelled (s) = ? m

[A] F = m × a

Or, a = (20/2) m/s² = 10 m/s²

Now, v² - u² = 2as

Or, 8² - 2² = 2.10.s

Or, s = 3 m [Ans.]

Hence, Work done is equal to the product of force and displacement, which will result in (20×3) J = 60 J.

[B] Distance travelled is 3 metre which we already got from the solution (A).