Question

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

Answer 1

Given :

Mass of the body, m = 20Kg

Initial velocity, u = 5m/s

Final velocity, v = 2m/s

To find:

Work done by the force

Solution :

We know that the Work done is always equal to the change in kinetic energy that is

$\boxed{\bf w = \dfrac{1}{2} mu^2 - \dfrac{1}{2} mv^2}$

where,

m denotes mass of the body, u denotes initial velocity and v denotes final velocity.

by substituting the given values,

$: \implies \sf w = \dfrac{1}{2}m( u^2 - v^2)$

$: \implies \sf w = \dfrac{1}{2}(20)( 5^2 - 2^2)$

$: \implies \sf w = 10( 25 - 4)$

$: \implies \sf w = 10(21)$

$: \implies \sf w = 210 \: J$

thus, work done by the force is 210 joules.

Answer 2

Answer:

Question

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

Given

• mass = 20 kg
• initial velocity= 5m/sec
• final velocity= 2m /sec

To find

the work by the force.

Solution

♦️ The work done by the object is equal to change in kinetic energy of an object.

It can be written as :-

${ \underline{ \boxed{ \sf{w = \frac{1}{2} m {v}^{2} - \frac{1}{2} m{u}^{2} }}}}$

where

• W denotes work
• m denotes mass
• v denotes final velocity
• u denotes initial velocity

substitute the values in the formula

$\sf{ \implies \: w = \frac{1}{2} m( {v}^{2} - {u}^{2} )} \\ \\ \sf{ \implies \: w = \frac{1}{2} \times 20 \times ( 4 - 25)} \\ \\ \sf{ \implies \: w = \frac{1}{2} \times 20 \times ( - 21)} \\ \\ \sf{ \implies \: w = - 210 \: J }$

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More to know !!

✒️Work is defined as product of the component of the force in the direction of the displacement and the magnitude of this displacement.

✒️ Dimension of work is :-

$\sf{ML²T {}^{ - 2} }$

✒️The SI unit of work is the joule (J),

✒️Work = Force × Displaced × cos∅

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