The certain force acting on a 20 kg mass changes its velocity from 5 m s-1 to 2 m s-1. Calculate the work done by the force.

A
$- 250 J$
B
$250 J$
C
$- 210 J$
D
$240 J$

Solution:

The certain force acting on a

20 kg

mass changes its velocity from

5 m s^{- 1}

2 m s^{- 1}

. The work done by the force is

- 210 J

.
Given data in the problem,
Mass,

m = 20 kg

Initial velocities,

u = 5 m s^{- 1}

Final velocity,

v = 2 m s^{- 1}

Work done, W = change in kinetic energy in mass

\Rightarrow W = {(E_{k})}_{f} - {(E_{k})}_{i}

\Rightarrow W = \frac{1}{2} m v^{2} - \frac{1}{2} m u^{2}

\Rightarrow W = \frac{1}{2} m [v^{2} - u^{2}]

\Rightarrow W = \frac{1}{2} \times 20 \times [2^{2} - 5^{2}]

\Rightarrow W = - 210 J

(Negative sign indicate that the work is done by object and its kinetic energy decreases.) A negative sign indicates that the work is done by the object and its kinetic energy is decreased.

The certain force acting on a $20 kg$ mass changes its velocity from $5 m s^{- 1}$ to $2 m s^{- 1}$ . Calculate the work done by the force.

Solution:

Related content

Company

Support

Courses

More

JEE

NEET

CUET

CBSE

Popular books

NCERT solutions

NCERT exemplar

State Board

Subject

follow us