Question

PHYSICS

1) A boy of mass 45 kg runs up a flight of 10 steps in 5 seconds. If each step is 50 cm. Calculate:
(i) The work done against gravity by the boy

Answer 1

2250 j

Step-by-step explanation:

mass = 45 kg

time = 5 sec

number of step =10

length of one step = 50 cm

so total length of step = 10× 50

= 500 cm

converting cm into metre

= 500/100

=5m

Now,

work done = force× displacement

= f×d

= m×g×d (f=m×g)

= 45× 10×5 ( g=10m/s^2)

= 2250 joule