Question

Certain force acting on a 20 kg mass changes its velocity from 5 m/s to 2 m/s.. calculate the work done by the force​

Answer 1

$\LARGE\mathfrak \pink{Solution:-}$

$\underline \mathbb{GIVEN:-}$

• Mass = 20 kg
• Initial velocity(u) = 5m/s
• Final velocity (v) = 2m/s

$\underline \mathbb{TO \: FIND:-}$

• Work Done.

$\underline \mathbb{FORMULA:-}$

Work Done = Change in Kinetic energy = Final Kinetic energy - Initial Kinetic energy.

Final Kinetic energy = $\frac{1}{2} m {v}^{2}$

Initial Kinetic energy = $\frac{1}{2} m {u}^{2}$

$\underline \mathbb{BY \: THE \: PROBLEM:-}$

Final kinetic energy =

$\frac{1}{2} m {v}^{2} \\ \\ \implies \: \frac{1}{\cancel{2}} \times \cancel{20}^{10 }\times {2}^{2} \\ \\ \implies 10 \times 4 \\ \\ \implies40 joule$

Initial Kinetic energy =

$\frac{1}{2} m {u}^{2} \\ \\ \implies \: \frac{1}{\cancel{2}} \times \cancel{20}^{10}\times {5}^{2} \\ \\ \implies \:10 \times 25 \\ \\ \implies \:250joule$

$Work \: Done \: = \: Final \: Kinetic \: energy \: - \: Initial \: Kinetic \: energy. \\ \\ \implies \:Work \: Done \: = 40joule - 250joule \\ \\ \implies \: Work \: Done \: = - 210joule$

$\underline \mathbb{ANSWER:-}$

$\implies \boxed{ Work \: Done \: = - 210joule}$

Answer 2

Answer:

-210 joule is the answer