physics
Meter Stick Meter Stick Meter Stick
The purpose of this experiment is to use the ballistic pendulum to determine the initial velocity of a projectile using conservation of momentum and conservation of energy as well as motion of projectiles.
Carbon Paper Meter Stick
Ballistic Pendulum
In this experiment a steel ball will be shot into the bob of a pendulum and the height, h, to which the pendulum bob moves, as shown in Figure 1, will determine the initial velocity, V, of the bob after it receives the moving ball.
If we equate the kinetic energy (KE) of the bob and the ball at the bottom of the potential energy (PE) of the bob and ball at the height, h, that they are raised to, we get:
KEbottom = PE top
½ (M + m) V2 = (M + m) g * h
where M is the mass of the pendulum and m is the mass of the ball. Solving for V we get:
V = √2gh .......... (1)
Using conservation of momentum we know the momentum before impact (collision) should be the same as the momentum after impact. Therefore:
mv0 = (M + m) V .......... (2)
Where v0 is the initial velocity of the ball before impact. By using equation (1) and (2) we can therefore find the initial velocity, v0, of the ball, with the combined equation of the two: V= (m+M/m)√2gh…..(3)
Trials
H2 (cm)
1
7.4
2
9.4
3
9.5
4
9.1
5
1.7
6
6.3
7
6.0
Avg.
7.9 H1=4.9 m=62.1g M=52.7g
V=18.32
We can also determine the initial velocity of the ball by shooting the ball as above but this time allowing the ball to miss the pendulum bob and travel horizontally and vertically, and then determine the initial velocity, v0, of the ball.
The purpose of this experiment is to use the ballistic pendulum to determine the initial velocity of a projectile using conservation of momentum and conservation of energy as well as motion of projectiles.
Carbon Paper Meter Stick
Ballistic Pendulum
In this experiment a steel ball will be shot into the bob of a pendulum and the height, h, to which the pendulum bob moves, as shown in Figure 1, will determine the initial velocity, V, of the bob after it receives the moving ball.
If we equate the kinetic energy (KE) of the bob and the ball at the bottom of the potential energy (PE) of the bob and ball at the height, h, that they are raised to, we get:
KEbottom = PE top
½ (M + m) V2 = (M + m) g * h
where M is the mass of the pendulum and m is the mass of the ball. Solving for V we get:
V = √2gh .......... (1)
Using conservation of momentum we know the momentum before impact (collision) should be the same as the momentum after impact. Therefore:
mv0 = (M + m) V .......... (2)
Where v0 is the initial velocity of the ball before impact. By using equation (1) and (2) we can therefore find the initial velocity, v0, of the ball, with the combined equation of the two: V= (m+M/m)√2gh…..(3)
Trials
H2 (cm)
1
7.4
2
9.4
3
9.5
4
9.1
5
1.7
6
6.3
7
6.0
Avg.
7.9 H1=4.9 m=62.1g M=52.7g
V=18.32
We can also determine the initial velocity of the ball by shooting the ball as above but this time allowing the ball to miss the pendulum bob and travel horizontally and vertically, and then determine the initial velocity, v0, of the ball.