if the sum of the external torques on an object is zero, then the sum of the external forces on it must also be zero.

How much work is done lifting a 9.10 kg box straight up onto a shelf that is 1.80 m high?

What happens to the light rays when they hit the specimen?

Imagine you had to physically add electrons, one at a time, to a previously neutral conductor. you add one electron very easily, but the second electron requires more work. in your initial post to the discussion, explain why this is. also, what happens to the work needed to add the third, fourth, fifth, and subsequent electrons