Question

A 2-kg box is pushed from rest to a speed of 29.7 m/s in 21 seconds. What is the power require to accelerate the box.

Answer 1

Answer:

594 watts

Explanation:

The information given is;

Mass of the box is 2 kg

Speed of the box is 29.7 m/s

Time is 21 seconds

We are required to determine the power;

Power is given by dividing work done by time

Power = Work done ÷ time

But; work done = Force × Distance

In this case;

Force = 2 kg × 10 N/kg

          = 20 N

Distance = speed × time

               = 29.7 m/s × 21

               = 623.7 m

Therefore;

Power = ( 20 N × 623.7 m) ÷ 21

            = 594 Watts

Therefore, the power that is required to accelerate the box is 594 watts

Answer 2

Answer:

P = 83.16 Watt

Explanation:

Given data:

Mass of box = 2 Kg

velocity of box = 29.7 m/s

Time = 21 sec

Power = ?

Solution:

Formula:

Power = work done/time

Now we will calculate the work done.

W = force × distance ...... (1)

d = speed /time

d = 29.7 m/s× 21 s

d = 623.7 m

Force:

acceleration = 29.7 m/s / 21 s

a = 1.4 m/s²

Force = m×a

Force = 2 kg×1.4 m/s²

Force = 2.8 N

Now we will put the values in equation 1.

W = F × d

W = 2.8 N ×623.7 m

W = 1746.36 Nm

Now for power:

P = W / time

P = 1746 Nm / 21 s

P = 83.16 Watt