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aero_zeppelin
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Homework Statement
A tennis ball of mass 0.022 kg is moving at 3.1 m/s at an angle of 222° to the horizontal. It is struck by a racket which exerts a force on it of 72t - 442 t^2 N for 1/10 of a second at an angle 32° to the horizontal. Find the final velocity of the tennis ball (Express answer using i and j unit vectors)
Homework Equations
So, I guess this is a momentum problem...?)
p = mv (momentum)
Δp = pf - pi
The Attempt at a Solution
My attempt here was the next:
1.- Integrate the force exerted by racket, using tf = 0.1 s and ti = 0
Δp = ∫ F dt = 0.218 Km m / s
2.- Divide Δp in x and y components, by multiplying 0.218 by cos 222° and sin 222°, respectively.
3.- Obtain ball's momentum, in components also:
px initial = (0.022 kg)(3.1 m/s) cos 32°
py initial = (0.022 kg)(3.1 m/s) sin 32°
4.- Using Δp = pfinal - pinitial, solve for pfinal, which is (mass)(vel. final), then solve for
vel. final.
v final = (Δp + p initial) / mass = (6.05 i + 3.2 j) m/s
That's what I got... They said integral calculus was not needed (even though it's a pretty easy integral) for this course I'm taking lol, but after some thinking this is the only way I think this can be solved.
Any comments? Any other way to solve it w/o integral calculus?
Thanks!