Chantelle W.
asked 11/01/15What was the cannonball's final speed when it hit the soldier?
If a cannonball was shot off 20 meters away from a soldier, and it's acceleration was 5m/s^2. What was the cannonball's final speed when it hit the soldier?
Hint: The Initial speed was 0m/s.
Show work please, thank you.
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2 Answers By Expert Tutors
We do not know how long is the barrel of the cannon, or what time it traveled through the barrel. But this should not prevent us from finding a solution.
Assume that the distance it traveled through the barrel of the cannon = d1
and the distance it traveled through air = d2
The total distance traveled by the cannonball = d1 + d2 = 20 m
In Barrel (a = 5m/s^2) In Air (5 seconds)
0 m/s-------------------------------------- v---------------------------v (hits soldier)
d1 d2 = 5 v
Using the equations of motion to find d1 and d2,
v^2 = 0 ^2 + 2 (5) d1 d1 = v^2 /10 d2 = 5 v
d1 + d2 = 20 meters v^2 /10 + 5 v = 20 v^2 + 50 v = 200
v^2 + 50 v - 200 = 0
Solve this equation using the quadratic formula to obtain v = 3.72 m/s

Mayuran K. answered 11/01/15
Tutor
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Patient and effective UH grad for High school Math tutoring
Use the equation
V^2 = u^2 + 2 as
V is the final velocity we need to find
V^2 = 0^2 + 2 * 5 * 20
V = sqrt 200
= 14.142 m/s
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Chantelle W.
11/01/15