Question

Morning breakfast gives 5000 cal to a 60Kg person.The efficiency of person is 30%.The height upto which the person can climb up by using energy obtained from breakfast is:

• A. $5m$
• B. $10.5m$
• C. $15m$
• D. $16.5m$

Answer 1

The correct option is B $10.5m$

n = Efficiency = 0.3

Ei = Energy input = 5000 cal

Energy used = n Ei

$=0.3\times 5000$

= 1500 cal.

$=1500\times 4.2$ Joule

$=6300J$

$6300=mgh$

$h=\frac{6300}{mg}$

$=\frac{6300}{60\times 10}$

$=10.5m$

Option (B)