Question

What is power expended by the engine of the car of mass 1.5 tones which increases the veloci
ty of the car from 36 km/hr to 72 km/hr in 20 second

Answer 1

$\huge\underline{\underline{\bf \orange{Question}}}$

What is power expended by the engine of the car of mass 1.5 tones which increases the velocity of the car from 36 km/hr to 72 km/hr in 20 second

$\huge\underline{\underline{\bf \orange{Solution}}}$

$\large\underline{\underline{\sf Given:}}$

• Mass ( m ) = 1.5 tones or 1500 kg
• ${\sf v_1=36\:km/h}$

In m/s ⎯

$\implies{\sf v_1 =36×\dfrac{5}{18}}$

$\implies{\bf v_1=10\:m/s}$

• ${\sf v_2=72\:km/h}$

In m/s ⎯

$\implies{\sf v_2=72×\dfrac{5}{18}}$

$\implies{\bf v_2=20\:m/s }$

$\large\underline{\underline{\sf To\:Find:}}$

• Power expended by engine of car ( P )

✪$\large{\boxed{\bf \blue{Power=\dfrac{Work\:Done}{Time\:Taken}}}}$

$\large\implies{\bf W =\dfrac{1}{2}mv_2^2-\dfrac{1}{2}mv_1^2 }$

$\implies{\sf \dfrac{1}{2}×1500(20^2-10^2) }$

$\implies{\sf \dfrac{1}{2}×1500×300}$

$\implies{\sf \green{W=225,000J}}$

$\large\implies{\bf P =\dfrac{W}{t} }$

$\implies{\sf P=\dfrac{225000}{20}}</p><p>$

$\implies{\bf \red{Power( P) =11250\:Watt}}$

$\huge\underline{\underline{\bf \orange{Answer}}}$

Power expended by engine of car is ${\bf \red{11250\:Watt}}$

Answer 2

$\huge\underline\mathrm{Answer-}$

Power expended by engine of car is ${\bf \red{11250\:Watt}}$