A force is applied on a body of mass $20 k g$ moving with a velocity of $40 m s^{- 1}$ . The body attains a velocity of $50 m s^{- 1}$ in $2$ seconds. Calculate the work done to attain this velocity.

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Solution

Force $= m \frac{(v - u)}{t} = m \cdot a$
Displacement $= \frac{(v^{2} - u^{2})}{2 a}$
Word done (W) $=$ Force $\times$ Displacement
$= m \cdot a \cdot \frac{(v^{2} - u^{2})}{2 a}$
W $= \frac{1}{2} m (v^{2} - u^{2})$
W $= \frac{1}{2} \times 20 \times (2500 - 1600)$
$= \frac{1}{2} \times 20 \times 900$
$= 9000 J$
Therefore, the work done to attain the final velocity is $9000 J$

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A force is applied on a body of mass 20kg moving with a velocity of 40ms−1. The body attains a velocity of 50ms−1 in 2 seconds. Calculate the work done to attain this velocity.

Force =m(v−u)t=m⋅aDisplacement =(v2−u2)2aWord done (W) = Force × Displacement =m⋅a⋅(v2−u2)2aW =12m(v2−u2)W =12×20×(2500−1600) =12×20×900 =9000JTherefore, the work done to attain the final velocity is 9000J

A force is applied on a body of mass $20 k g$ moving with a velocity of $40 m s^{- 1}$ . The body attains a velocity of $50 m s^{- 1}$ in $2$ seconds. Calculate the work done to attain this velocity.