Physics 12th Grade
posted by Sarah on .
An archer puts a 0.34 kg arrow to the bowstring. An average force of 220 N is exerted to draw the string back 1.3 m. Assume that air resistance is negligible. If the arrow is shot straight up, how high does it rise?
I am confused at how to find the distance that it will rise.

The work done drawing the bow is
W = (average force)*(distance pulled)
= 286 Joules
Set that equal to the potential energy gained at highest altitude, H
M g H = 286 J
H = 286/(0.34*9.8) = ____?
Note that kinetic energy does not enter into the equation at highest altitude because the arrow is temporarily motionless there. 
Two girls with masses of 50.0 kg and 70.0 kg are at rest on frictionless inline skates. the larger girl pushes the smaller girl so that the latter rolls away at a speed of 10.0 m/s. What is the effect of the action on the larger girl? What is the impulse that each girl exerts on the other?

dunno