Physics Power and Work

Question

A 49kg bicycle rider delivers an average of 0.28 hp. The mass of the bicycle is 2.1kg and the hill she is climbing is 245m tall. How much time will this take?

Answer 1

The conversion from horse power to watt is  1 hp = 745.7 W.   So  0.28 hp = 208.8 W

 

The total mass that must be raised 245 m is:  m =  49 + 2.1 = 51.1 

 

The work that must be done is:  W = m g h = (51.1) (9.81) (245) = 122816 J

 

Finally work is power multiplied by time   So:  W = 208.8 T  

and  T =  122816 / 208.8 =  588 s.