I am not too sure whether I am doing this correctly.(adsbygoogle = window.adsbygoogle || []).push({});

The problem is basically a mini-cannon aimed at a 60 degree angle, hits a target on the ground 0.8m away. I am suppose to find the initial velocity.

This is what I did:

Cut the distance in half, assuming the mini cannon-ball will reach its maximum height at that point (and v = 0). Which is 0.4 m. I then use trig, and do the following: tan60 = y/0.4; y = 0.693m

vf^2 - vi^2 = 2a(xf-xi)

vf^2 - 0 = 2(-9.8m/sT=^2)(0.693m)

vf = 3.68 m/s from top of height to ground

so vi = 3.68 m/s

So this is the velocity of the y component?

Then:

tan 60 = (3.68 m/s) / x

xtan(60) = 3.68 m/s

x = 3.68/tan60 = 2.12 m/s

v(total)^2 = vy^2 + vx^2 = (3.68 m/s)^2 + (2.12 m/s)^2

v(total) = 4.25 m/s?

Is that correct? Did I do anything wrong?

[I also did this, but I don't think I need it.

vf = vi + at

0 = 3.68 m/s + (-9.8 m/s^2)(t)

t = 0.376 s ]

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# Homework Help: Projectile motion of mini cannon ball

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