a man whose mass is 75 kg walks up to 10 steps, each 20 cm high, in 5sec .what is the work done?
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Sra
The work done does not depend upon how long it takes. (But the POWER does). Work is the product of mass, the acceleration of gravity, and the elevation gain.
In your case, that is
W = M g H = 75 kg*9.8 m/s^2*2.0 m
= 1470 Joules
To calculate the work done by the man, we need to use the formula:
Work = Force × Distance
In this case, the force required to do the work is equal to the weight of the man. The weight of an object is calculated using the formula:
Weight = mass × gravitational acceleration
where the gravitational acceleration on Earth is approximately 9.8 m/s².
Let's break down the solution step-by-step:
First, calculate the weight of the man:
Weight = mass × gravitational acceleration
Weight = 75 kg × 9.8 m/s²
Weight = 735 N (Newtons)
Next, calculate the total vertical distance the man has lifted himself:
Total Distance = number of steps × height of each step
Total Distance = 10 steps × 0.20 m (20 cm = 0.20 m)
Total Distance = 2 m
Now, substitute the values into the formula for work:
Work = Force × Distance
Work = 735 N × 2 m
Work = 1470 N·m or 1470 J (Joules)
Therefore, the work done by the man while walking up 10 steps each 20 cm high in 5 seconds is 1470 Joules.