Question

On applying a force of 15N. for 6 sec, a man displaces a box by 8m. Calculate his power.​

Answer 1

Given that;

• Magnitude of force = 15 N
• Time interval = 6 s
• Displacement = 8 m

We are asked to calculate power.

★ We know that power is defined as the work done per unit time.

Mathematically,

$:\implies\:\underline{\boxed{\bf{\red{Power=\dfrac{Work}{Time}}}}}$

• It is a scalar quantity having only magnitude.
• SI unit : watt (W)

First of all we have to calculate work done which is defined as the dot product of force and displacement.

→ Work = F d

→ W = 15 × 8

→ W = 120 J

By substituting the values in the formula of power;

$\sf:\implies\:P=\dfrac{W}{t}$

$\sf:\implies\:P=\dfrac{120}{6}$

$:\implies\:\underline{\boxed{\bf{\gray{P=20\:W}}}}$

Answer 2

Answer:

Explanation:

force applied(f) = 15N

time(t) = 6 seconds

displacement(s) = 8m

since,

power = work done/time taken

∴ work done = f * s

                      =  15 * 8

                       = 120joules

now,

power = 120/6

                   = 20watt