A man whose mass is75kg walks up a stairs of 12steps each 20cm high in 5seconds.calculate the power expended in watts.[assume g=10m\s2

m g h / t ... 75 * 10 * 12 * .20 / 5

360

M=75kg T=5sec distancE(s)=12*12=240cm=2.4m f=mg=75*10=750N P=F*S =750*2.4=360W T 5

To calculate the power expended by the man while walking up the stairs, we need to use the formula:

Power (P) = Work (W) ÷ Time (t)

First, let's calculate the work done by the man. Work is calculated as the force applied multiplied by the distance traveled. In this case, the force is equal to the weight of the man, which can be calculated using the formula:

Weight (W) = mass (m) × acceleration due to gravity (g)

Given that the mass of the man is 75 kg and the acceleration due to gravity is 10 m/s^2, we can calculate the weight:

Weight (W) = 75 kg × 10 m/s^2
= 750 N

Next, we need to calculate the distance traveled by the man. Since each step is 20 cm high, and there are 12 steps, the total vertical distance traveled is:

Distance (d) = height of each step × number of steps
= 0.2 m × 12
= 2.4 m

Now, we can calculate the work done:

Work (W) = Force (W) × Distance (d)
= 750 N × 2.4 m
= 1800 J (Joules)

Finally, we can use the given time of 5 seconds to calculate the power:

Power (P) = Work (W) ÷ Time (t)
= 1800 J ÷ 5 s
= 360 W (watts)

Therefore, the power expended by the man while walking up the stairs is 360 watts.