PHYS 121 

Lab Activity Report 
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Other members of your lab group (up to 3 total including yourself)
____________________________  ____________________________ 
procedure:
results:
What "range" have you selected? _______________________
M (g)  m (g)  R (cm) 
Record the angle for several trials:
n  θ (°) 
1  
2  
3  
4  
5  
6  
average 
Compute the muzzle velocity of the ball?
Since the muzzle velocity of the ball is quite low, another way to determine the muzzle velocity of the ball is to measure the horizontal distance for the ball to strike the floor.
Derive an equation for the initial muzzle velocity, assuming it is horizontal, in terms of the initial height, y_{0}, above the floor and the horizontal distance to impact, x.
The initial height of the ball above the floor, y_{0} = _______________ (m)
n  x (m) 
1  
2  
3  
4  
5  
6  
average 
Compute the initial muzzle velocity from the average x.
Compare this value with the value you obtained from the ballistic pendulum. Which is larger? What is the percent difference?
The ball sometimes rolls forward in the launcher instead of resting against the spring. What effect does this have on the muzzle velocity?
What relevant suggestions do you have that might improve the results of this lab activity?