# Homework Help: Finding Final Velocity by Energy Techniques

1. Oct 13, 2004

A 1.50 kg snowball is fired from a cliff 13.5 m high with an initial velocity of 14.0 m/s, directed 41.0° above the horizontal.
(a) Using energy techniques, rather than techniques of Chapter 4, find the speed of the snowball as it reaches the ground below the cliff.
ok so I used the equation k1+u1=k2=u2
plugging in numbers i did 1/2(1.50kg)(14m/s)^2+(1.50kg)(9.8m/s^2)(13.5m)=1/2(1.50kg)(vf)^2+(1.50kg)(9.8m/s)(0). Then I solve for Vf and I get a wrong answer. Now i realize this is probably wrong since I haven't incorporated the angle, but I'm not sure. Any ideas?

2. Oct 13, 2004

### Galileo

Well. The technique is right, so you must've made some silly error in solving for Vf.
What answer did you get? It should be 21.5 m/s.

3. Oct 13, 2004

Yeah 21.5 is the answer, guess I must have made a mistake with the calculator . Thank You

4. Oct 13, 2004