How Long to Reach Maximum Height for a 70 m/s Projectile at 45 Degrees?

[Cortana]

Homework Statement

A projectile was launched at 70 m/s at an angle of 45 degrees above the horizontal, how long does it take the projectile to reach maximum height?

Homework Equations

Vyo= initial vertical velocity Vo=initial velocity

The Attempt at a Solution

I tried using the equation Vxo=VoSIN(theta)

 

[cnh1995]

Welcome to PF!

I tried using the equation Vxo=VoSIN(theta)

No.
You need to show what you've tried so that we can see what went wrong.

 

[Cortana]

I don't even know where to start tbh, i don't even know which formula to use

 

[cnh1995]

I don't even know where to start tbh, i don't even know which formula to use

Have a read (especially rule no 4).
https://www.physicsforums.com/threads/guidelines-for-students-and-helpers.686781/

 

[haruspex]

I tried using the equation Vxo=VoSIN(theta)

Did you mean that? It could be right, depending on how exactly you are defining theta. What angle do you think it represents?
Double check your source for that equation.

 

[thejosh]

try using trig ratios and SUVAT equations