Question

Bart runs up a 2.91 meters high flight of stairs at a constant speed in 2.15 seconds. If barts mass is 65.9kg determine the work which he did and his power rating

Answer 1

Answer:

1879.33J

874.1W

Explanation:

Given parameters:

Distance covered  = 2.91m

Time taken  = 2.15s

Mass of Bart = 65.9kg

Unknown:

Work done  = ?

Power rating  = ?

Solution:

Here, the work done is related to the the potential energy in climbing this flight of stairs.

  Work done = Potential energy  = mgH

where m is the mass

           g is the acceleration due to gravity

           H is the height

Work done  = 65.9 x 9.8 x 2.91  = 1879.33J

Power is defined as the rate at which work is being done.

         Power = $\frac{Work done }{time taken}$

                     = $\frac{1879.33}{2.15}$

                      = 874.1W