Question

2. The second activity basically involves the torque due to the weight of the ruler versus the torque due to the weight of the coins. You observe that the more coins there are, the closer the coins need to be to the pivot point (i.e. the edge of the table) for the ruler to be on the verge of falling over. Why?

a. None of the choices.

b. The lever arm of the weight of the ruler needs to increase while the lever arm of the weight of the coins needs to decrease for the two torques to balance out.

c. The bigger the weight of the coins, the bigger the weight needed to balance it out; hence, more of the ruler needs to over the edge of the table.

d. The more coins there are, the bigger the normal force magnitude that needs to considered in determining the total torque of the system.

Thanks!!

Answer 1

Suppose there are more number of coins and if you put it at large distance from edge of table then the lever arm will be greater. Hence the torque about the pivot will be greater.

Because torque T=l*F ......wher l is length upto coins

There to kepp the ruler on verge of falling, you have to keep coins as much closer asoas to the table and increase the lever of ruler arm. So that the torque gets balances out and ruler will not fall.

Hence option b is correct.

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