Two scales support a massless plank from either end, separated by 3 m. A person, whose height is less than 3 m, lies down on the plank with their head on the leftmost scale. The leftmost scale reads 314 N, and the rightmost scale reads 112 N.

Question

Two scales support a massless plank from either end, separated by 3 m. A person, whose height is less than 3 m, lies down on the plank with their head on the leftmost scale. The leftmost scale reads 314 N, and the rightmost scale reads 112 N.
(a)	
Calculate the person’s mass, in kg.
(b)	
What is the location, in metres from the person’s head, of their centre of mass?

johnny · Answer

A spiral spring of nature 20cm,has a scale pan hanging freely in its lower end. When an object of mass 40g is placed in the pan,its length becomes 21.8cm.when another object of mass 60g is placed in the pan,the length becomes 22.05cm. Calculate the mass of the scale pan