Question

Force acts on 50 kg mass changes it’s velocity from 10 m/s to 20 m/s calculate the work done

Answer 1

Mass of the particle = 50 kg

Initial velocity = 10 m/s

Final velocity = 20 m/s

According to the work - energy theorem,

W = ∆KE = ½ m(v + u)(v - u)

⇒ W = ½ 50(20 + 10)(20 - 10) J

⇒ W = 25(30)(10) J

⇒ W = 7500 J or 7.5 kJ.

∴ Work done on the particle was of 7.5 kJ.

Answer 2

Mass of the object, m = 50 kg

Initial velocity of the object, u = 10 m/s

Final velocity of the object, v = 20 m/s

Work done by the object = W

By using the formula, W = $\sf ∆E_k$

• $\sf E_k$ = $\dfrac{1}{2}$mv²

• $\sf ∆E_k$ = $\dfrac{1}{2}$m (v² - u²)

• $\sf ∆E_k$ = $\dfrac{1}{2}$ × 50 × 300

• $\sf ∆E_k$ = 7500 J

• $\sf ∆E_k$ = 7.5 kJ

OR

• W = F × s

• W = ma × $\dfrac{v^2 - u^2}{2a}$

• W = 50 × $\dfrac{300}{2}$

• W = 7500 J

• W = 7.5 kJ

$\textbf{I\;hope\;it'll\;be\;helpful!}$