A car of mass $2000 k g$ changes its speed from $18 k m / h$ to $90 k m / h r$ . Find the work done by the engine.

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Solution

Given,
$m = 2000 k g$
$u = 18 k m / h r = 18 \times \frac{5}{18} = 5 m / s$

$v = 90 k m / h r = 90 \times \frac{5}{18} = 25 m / s$

Work done by the engine $=$ Change in kinetic energy
$W = \frac{1}{2} m (v^{2} - u^{2}) = \frac{1}{2} \times 2000 (25^{2} - 5^{2}) = 600000 J$
$W = 600 k J$

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A car of mass 2000 kg changes its speed from 18 km/h to 90 km/hr. Find the work done by the engine.

Given,m=2000 kgu=18 km/hr=18×518=5 m/sv=90 km/hr=90×518=25 m/sWork done by the engine = Change in kinetic energyW=12m(v2−u2)=12×2000(252−52)=600000 JW=600 kJ

A car of mass $2000 k g$ changes its speed from $18 k m / h$ to $90 k m / h r$ . Find the work done by the engine.

Given,
$m = 2000 k g$
$u = 18 k m / h r = 18 \times \frac{5}{18} = 5 m / s$

$v = 90 k m / h r = 90 \times \frac{5}{18} = 25 m / s$

Work done by the engine $=$ Change in kinetic energy
$W = \frac{1}{2} m (v^{2} - u^{2}) = \frac{1}{2} \times 2000 (25^{2} - 5^{2}) = 600000 J$
$W = 600 k J$