Question

6d A boy pushes his little brother on a sled. The sled accelerates from rest to (4 m/s). If the combines of his brother and the sled is (40.0 kg) and (20 W) of power is developed, how long time does the boy push the sled?​

Answer 1

16 s

Step-by-step explanation:

From the question given above, the following data were obtained:

Mass (m) = 40 Kg

Velocity (v) = 4 m/s

Power (P) = 20 W

Time (t) =?

Next, we shall determine the energy. This can be obtained as follow:

Mass (m) = 40 Kg

Velocity (v) = 4 m/s

Energy (E) =?

E = ½mv²

E = ½ × 40 × 4²

E = 20 × 16

E = 320 J

Finally, we shall determine the time. This can be obtained as follow:

Power (P) = 20 W

Energy (E) = 320 J

Time (t) =?

E = Pt

320 = 20 × t

Divide both side by 20

t = 320 / 20

t = 16 s

Thus, the time is 16 s