Neglect air resistance in all cases.
(a) A branch falls from the top of a 76.0-m-tall redwood tree, starting from rest. How fast is it moving when it reaches the ground?

(b) A volcano ejects a boulder directly upward 530 m into the air. How fast was the boulder moving just as it left the volcano?

(c) A skier moving at 4.50 m/s encounters a long, rough horizontal patch of snow having coefficient of kinetic friction 0.220 with her skis. How far does she travel on this patch

Question

Neglect air resistance in all cases.
(a) A branch falls from the top of a 76.0-m-tall redwood tree, starting from rest. How fast is it moving when it reaches the ground?
 
(b) A volcano ejects a boulder directly upward 530 m into the air. How fast was the boulder moving just as it left the volcano?

(c) A skier moving at 4.50 m/s encounters a long, rough horizontal patch of snow having coefficient of kinetic friction 0.220 with her skis. How far does she travel on this patch

jfraser · Answer

what is the work-energy theorem?

anonymous · Answer

http://faculty.wwu.edu/vawter/PhysicsNet/Topics/Work/WorkEngergyTheorem.html

jfraser · Answer

let me rephrase that:

I know what the W-E theorem says, do you? I don't mean to cut and paste a definition, I mean can you $describe$ what it means?

anonymous · Answer

not really

jfraser · Answer

it means that work must be done in order to change an object's energy, and that work and energy are really both the same kind of thing. We measure work done in Joules, and change in energy in Joules as well