14 Jan 11 Physics quiz tomorrow and i really need help on a ?

Question by daydreamer: Physics quiz tomorrow and i really need help on a ?
im studying for a quiz tomorrow and i don’t understand this question.

A spring-driven dart gun propels a 10 gram dart. It is cocked by exerting a force of 20N over a distance of 5.0 cm. How fast will the dart leave the gun? Find the speed?

and help or somewhat of an explanation on what formula/what to do? Any help is greatly appreciated!!

Best answer:

Answer by Hahaha
Thinking about work and energy.
So the force did work on the dart. The work has been informed to you as force times the distance: 20N*5.0cm = 1J.
This work is to be converted to the kinetic energy of the dart, which is 0.5*m*v^2. That is to say:
2J = (0.01kg)*v^2. v is easily figure out to be 10√2 (m/s).

Know better? Leave your own answer in the comments!