Question

a person wwho weighs 670N runs 7m in 1.6s. If he accelarated uniformly find his power in kilowatts(take g=10m/sec^2)

Answer 1

Hey dear,

● Answer -
P = 3.207 kW

● Explaination -
# Given -
s = 7 m
t = 1.6 s
W = 670 N

# Solution -
Mass of the man -
m = W / g
m = 670 / 10
m = 67 kg

Usimg Newton's 2nd law of motion -
s = ut + 1/2 at^2
7 = 0×1.6 + 0.5×a×(1.6)^2
7 = 1.28a
a = 5.47 m/s^2

Using Newton's 1st law,
v = u + at
v = 0 + 5.47×1.6
v = 8.75 m/s

Power of the man can be calculated as -
P = Fv = mav
P = 67 × 5.47 × 8.75
P = 3207 W
P = 3.207 kW

Therefore, power of the man is 3.207 kW.

Hope this helps you...