A person whose mass is m = 70.0 kg m=70.0 kg steps on a mechanical bathroom scale placed on an inclined plane that makes the angle α = 22.3 ∘ α=22.3∘ with the horizontal. What is the reading on the scale?

The reading on the scale is 64.76kg

Explanation:

According to Newton's 3rd law,when a person exerts a force on a plane,the plane simultaneously exerts a force equal in magnitude and opposite.

Given: mass=70kg ,alpha= 22.3°

Mg=mg×cos alpha= 70kg× cos22.3°=

70× 0.9252= 64.76kg

The reading on the scale is 64.76kg

work: w = fd (given)

work done by chet   =50*1 = 50 j

work done by mika =40*2 = 80 j

work done by sara =30*1.5 = 45 j

work done by bill =60*0.5 = 30 j

students in order from the greatest amount of work done to the least is mika> chet> sara> bill

hence option (b) is correct.

change tension