Question

Michael estimated his mass as 8 kilograms. Is his estimate reasonable? Justify your answer.

Answer 1

Answer:  The answer is Yes.

Step-by-step explanation:  Given that Michael estimated his mass and found it to be 8 kilograms. It may sound awkward to us, but its true. Because when we measure our weight by the weight machine it gives us the product of our actual mass and the acceleration due to gravity.

From second law of motion, we have

Weight = mass × acceleration due to gravity.

That is, W = m × 9.8 m/sec².

The unit of mass is kilogram and 1 kg m/sec² = 1 Newton. Therefore, the unit of the weight we generally measure is Newton (N), not kilogram. Here is what we make mistake usually.

Thus, if Michael' mass is 8 kg, then his weight will be

W = 8 × 9.8 kg m/sec² = 78.4 N, which is normal weight of a person.

Thus, his estimation is perfectly OK.