Question

. A coolie carrying a briefcase weighing 4 kg climbs down 10 stairs each of 0.05 m high in a railing platform. He then walks along a horizontal frictionless road a distance of 20 m. The work done by the coolie is​

Answer 1

for convenience we take g=10m/s

w= f × s

f = M × g

= 4 × 10

= 40 N

s = 5/100 × 10 = 0.5m + 20m = 20.5m

w = f × s

= 40 N × 20.5m

= 40 × 205/10

= 820 Nm

= 820 J