Question

A man speeds $6.4kg$ energy in displacing his body $64m$ in the direction in which he applies force in $2.55N$. Calculate the power spent $\left( {in{\text{ }}hp} \right)$ by the man.
A. $34.3hp$
B. $343hp$
C. $0.343hp$
D. $3.43hp$

Answer 1

Power is the rate at which energy is transferred or the rate at which work is done
$p = \dfrac{w}{e}$ where $w =$work is done and $t =$time in sec.

Complete step by step answer:
We know that in physics power is the amount of energy transferred or connected per unit time.
In the international system of units the power is the watt.

Power is a scalar quantity.
Hence,
Power $\; = \dfrac{{work}}{{time}}$
Given energy or work is equal to $6.4kJ$ that is also equal to $6400J$ conversion.
$1kJ = 1000J$
$Power = \dfrac{{6400}}{{2.5 = 2560W}}$
$1hp = 746watts$
Hence power is equal to $\dfrac{{2560}}{{746}} = 3.43HP$

So, the correct answer is “Option D”.

Note:
Power is the ratio of the work to the elapsed time $p = \dfrac{w}{{\Delta t}}$
The work is given and the time is also given then we can easily calculate the power.