Different masses are hung on a spring scale calibrated in newtons. the force exerted by gravity on 1.0 kg is shown in the image below in newtons.

an image of a spring scale with a 1 kilogram weight attached. the scale reads 9.8 n.

what would be the force exerted by gravity on 6.5 kg?

6.5 n
9.8 n
64 n
98 n

F = 64 N

Explanation:

When 1 kg of weight attached with the spring, the scale reads 9.8 N. Weight of an object is the product of mass and acceleration due to gravity. Let F is the force exerted by gravity on 6.5 kg. It can be calculated as :

F = 63.7 N

or

F = 64 N

So, the force exerted by gravity on 6.5 kg is 64 N.

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.

the answer is b i think