Question

in 1984 don, disk that stayed aloft for 16.7 seonds supsuppose cain ran up a staricase during this time, reachig a height of 18.4 m if his mass was 72 kg how much powerwas needed for his ascent

Answer 1

Answer

given,

time of disk stayed a loft = 16.7 sec

height reached = 18.4 m

mass  = 72 kg

now work done is equal to change in potential energy

$W = - (U_f - U_i)$

$W = - (mgh - 0)$

$W = - (72\times (-9.8) \times 18.4)$

W = 12983.04 J

Positive sign means that work is in the direction of motion.

$Power = \dfrac{Work\ done}{time}$

$Power = \dfrac{W}{t}$

$Power = \dfrac{12983.04}{16.7}$

P = 777.42 Watts