How Do You Calculate the Initial Velocity Components of a Projectile?

[kara]

So the horizontal component of my initial velocity is 20 m/s, and the vertical component of initial velocity is 36.6 m/s

 

[kara]

Now i have to calculate how far is its displacement horizontally from launch pt, at the instant it achieves max height.

So i know that its v will be 0 m/s at max heigh.

 

[Doc Al]

So i know that its v will be 0 m/s at max heigh.

Right... the vertical component of the velocity will be zero.

 

[kara]

and b/c I am looking for how far its been displaced horizontally from the launch pt. i am looking for x?

 

[kara]

so i can solve for t in the y=y0 + v0-1/2gt^2 equation and sub t into x=x0 +v0t equation and solve for x

 

[Doc Al]

and b/c I am looking for how far its been displaced horizontally from the launch pt. i am looking for x?

That's right. You are looking for the value of x when y is maximum. Hint: When does it reach the maximum height?

 

[kara]

well the max height is 53 m, and it reaches that height when v = 0.0 m/s

 

[kara]

i plugged in all my values but get stuck at one point with a negative square root:

53 = -1/2(9.8)t^2

 

[kara]

if i multiply both sides by 2 to get rid of the 1/2 i get

106 = -(9.8) t^2

 

[Doc Al]

i plugged in all my values but get stuck at one point with a negative square root:

53 = -1/2(9.8)t^2

You left out part of that equation; it should be:
53 = v0t -1/2(9.8)t^2

Where v0 is the vertical component of initial velocity that you found earlier.