- #1
Dorothy Weglend
- 247
- 2
A toy cannon uses a spring to project a 5.30g soft rubber ball. Spring is compressed 5.00 cm, k=8.00 N/m. Barrel is horizontal.
The ball moves 15.0 cm through the barrel, with friction force of 0.0320 N between thebarrel and the ball. With what speed does the projectile leave the barrel of the cannon?
I thought this problem was simple, but the answer 'in the back' is different from what I am getting, so I thought I would ask for some help.
I use
mv^2/2 = kx^2/2 - fk(x+d)
x = compression of spring, d = distance along the barrel, so
m = 5.32 * 10^-3 m,
k = 8 N/m
x = 0.05 m
k = 8 N/m
fk = 0.032 N
d = 0.15 m
With these figures, I get v = 1.17 m/s.
The answer in the back is 1.40 m/s.
Can anyone see where I am going wrong?
Dorothy
The ball moves 15.0 cm through the barrel, with friction force of 0.0320 N between thebarrel and the ball. With what speed does the projectile leave the barrel of the cannon?
I thought this problem was simple, but the answer 'in the back' is different from what I am getting, so I thought I would ask for some help.
I use
mv^2/2 = kx^2/2 - fk(x+d)
x = compression of spring, d = distance along the barrel, so
m = 5.32 * 10^-3 m,
k = 8 N/m
x = 0.05 m
k = 8 N/m
fk = 0.032 N
d = 0.15 m
With these figures, I get v = 1.17 m/s.
The answer in the back is 1.40 m/s.
Can anyone see where I am going wrong?
Dorothy