Question

a- Define I watt of power?
b- A boy of mass 30 kg runs up a staircase of 60 steps each of 25cm in 15s.
A girl of mass 40 kg runs the same distance in 10 sec. Find the ratio of their
work done and the ratio of their power?​

Answer 1

Answer:

1 watt is the amount of Power where 1 J of work is done in a time of 1 second.

Given,

Boy Mass (m₁) = 30 kg

No. of staircase (n) = 60

Height of each staircase (h) = 25 cm

= 0.25 m

Total Height travelled by the boy (d) = [60*0.25] m

= 15 m

Acceleration due to gravity (g) = 9.8 m/s²

Work Done (W₁) = Force*Displacement

= m₁*g*d

= 30*9.8*15 J

= 4410 J

Time (t₁) = 15 s

Power (P₁) = W₁/t₁

= 4410/15 W

=  294 W

Mass of girl (m₂) = 40 kg

d = 15 m

Work Done (W₂) = Force*Displacement

= m₂*g*d

= 40*9.8*15 J

= 5880 J

Time 2 (t₂) = 10 s

Power (P₂) = W₂/t₂

= 5880/10

= 588 J

Ratio of Work Done = W₁:W₂

= 4410:5880

= 441:588

= 147:196

= 21:28

= 3:4

Ratio of Power = P₁:P₂

= 294:588

= 1:2

Ratio of Work Done is 3:4 and Power is 1:2.

I hope this helps.