Finding maximum Height

• pennywise1234
In summary, the question is asking for the maximum height achieved by a soccer ball kicked at a 45° angle and in the air for 3 seconds. To solve this, the vertical and horizontal components were calculated using trigonometry, resulting in 2.2 for each side. The equation used to find the maximum height was incorrect, and after corrections were made using the correct equation, it was found that the initial velocity could be calculated by creating an unknown, v, and using the vertical displacement at time t and when the ball lands.

Homework Statement

A soccer ball is kicked at a 45° angle. If the ball is in the air for 3 s, what is the maximum height achieved

Homework Equations

y=viy + 0.5 x ay x t

The Attempt at a Solution

i used trig to get the vertical and horizontal components i got 2.2 for each side (as there the same with a 45 degree angle)

i used y=0 + 0.5 x (-9.81) x (3s)

is this right ^^

i used y=0 + 0.5 x (-9.81) x (1.5s)Square root

is what i meant to put

I think you mean squared, not square root.

yes, sorry

pennywise1234 said:
i got 2.2 for each side
You got 2.2 what? You don't know the velocity, so how can you get the velocity components?

y=o represents initial velocity. but it is not known like you said, so that is how i was able to get 11.05 but setting initial to 0

The initial velocity cannot be 0. Otherwise, with gravity being the only accelerator the projectile would go down.

It's possible to calculate your initial velocity though, assuming the projectile lands on level ground. Can you modify your relationship above to help you find this?

pennywise1234 said:
y=o represents initial velocity. but it is not known like you said, so that is how i was able to get 11.05 but setting initial to 0
Setting it zero will get you nowhere. Create an unknown for it, v.
Your equation for y is suitable for a vertical displacement, not a vertical velocity. In terms of v, what would the vertical displacement be at time t? What is the vertical displacement when it lands?

I am trying to find displacement though

pennywise1234 said:
I am trying to find displacement though
You are asked to find, eventually, the vertical displacement from launch to the highest point. I asked you what the vertical displacement is from launch to where it lands.