Question

Q-While performing an experiment to establish the relationship between weight of a rectangular wooden block lying on a horizontal table and the minimum force required to just move it using a spring balance. If the weight of block is 73 g wt then the most suitable spring balance will be of: (a) Least count 1 g wt, range 100 g wt. (b) Least count 2.5 g wt, range 500 g wt. (c) Least count 2 g wt, range 400 g wt. (d) Least count 10 g wt, range 100 g wt.

Answer 1

The relationship between the weight W of the block and the force F required is the coefficient of friction μ.   As usually 0 <= μ <= 1, force F <= W or 73 g wt.  In this experiment, we are trying to measure F.

So we need a balance that has range >= 73 g wt and the most accurate one.  That is with the smallest least count.

So the option is   (a)   LC= 1 gm wt   , Range 100 g wt