- #1
Ready2GoXtr
- 75
- 0
Homework Statement
A 300g ball with a speed v of 6.0m/s strikes a wall at an angle theta of 30 degrees and then rebounds with the same speed and angle. It is in contact with the wall for 10ms. In unit-vector notation, what are (a) the impulse on the ball from the wall and (b) the average force on the wall from the ball?
http://ready2goxtr.googlepages.com/problem936.jpg
Homework Equations
Pi = Pf
Delta (P) = I
P = mv
<v being a vector>
Favg = I / (delta T)
The Attempt at a Solution
m = .3kg v = 6m/s theta = 30 degrees t = 10ms = .01s
a) Pi = PF
Pi = .3kg(Vcos(-30) i + Vsin(-30) j) = .26 kg * m/s i - 3 kg * m/s j
Pf = .3kg(Vcos(30) i + Vsin(30) j) = .26 kg * m/s i + 3 kg * m/s j
I = Delta (P) I = PF - PI
PF - PI = 6 kg * m/s j
b) I = sqrt(a^2 + b^2)
6kg * m/s / .01s = 600 N
I know i did it wrong. And thank you ahead of time.