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(1) A hand exerts a constant horizontial force on a block that is free to slide on a frictionless surface. The block starts from rest at point A, and by the time it has traveled a distancedto point B it is traveling with speedvB. When the block has traveled another distancedto point C, will it's speed be greater than, less than, or equal to 2vB? Explain your reasoning.

My drawling, if you can undertand it...

Hand pushes block----------------------------------------<(surface)

~~~~~~~~~~~A----d----B----d----C

My first instinct is to say equal to since it is a frictionless surface therefore nothing will slow it down.

(2) Seasoned hikers prefer to step over a fallen log in their path rather than stepping on top and jumping down on the other side. Explain.

No idea... but I was thinking because it takes twice as much energy to step on top of and then down than it does to just stepp over?

(Thanks to all who help)

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# Homework Help: Solving these non-numerical problems applying work and energy concepts

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