How Do You Solve for the Time Given Initial Velocity and Angle?

[papa_smurf493]

Homework Statement

A left-handed pitcher at sea level throws a baseball at a 45o angle with an initial speed of 19 m/s. The time for the ball to reach its highest point can be found from the data and known constants using which equations? Solve for the time.

Homework Equations

V^2 = Vi^2 + 2(a)(y)
y = (Vi)(t) + 1/2(a)(t^2)

The Attempt at a Solution

V^2 = Vi^2 + 2(a)(y)
0 = 13.435^2 + 2*9.8*y
y = 9.21 meters

9.21 = 0 + 0.5*9.8*t^2
9.21 = 4.9*t^2
t = 1.37 seconds

 

[PhanthomJay]

Yes, correct, but you could have shortened your work by using just one simpler equation. Can you identify that equation?

 

[yoleven]

Looks okay.
I used this:
V_{f}=V_{i}+at

velocity at the highest point is 0, so..

0m/s =19m/s sin45°-9.8m/s^{2} *t
t=1.37s