Question

What horsepower is necessary to lift 180 tonnes of coal per hour, from a mine 120 m deep? (Ans. 78.82 hp)​

Answer 1

100Kw

m = 105kg,g=10ms−2,h=360m,t=1h=3600s

The work needed in lifting a mass m to a height h against the force due to gravity is W=mg×h

And, power, P=tW=tmgh

∴P=3600105×10×360W=105W=100kW

Hope it helps..

mark as brainliest answer

Answer 2

Answer:

60,000 W or 80.46 HP

Explanation:

m= 180 tonnes

1 tonne = 1000kg = 10⁴kg

t= 1 hr = 60 mins

1 min = 60 secs,

1 hr = 60× 60 = 3600s

g= 10 ( constant)

h= 120

W= mgh

P= W/t

W = mgh

W = 180× 10⁴ × 10 × 120

= 216 × 10⁷

P= (216× 10⁷)/3600

= 60,000 W or 80.46 HP