# Will you check my work?

1. Feb 3, 2009

### papa_smurf493

1. The problem statement, all variables and given/known data
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.

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

3. 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

2. Feb 3, 2009

### PhanthomJay

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

3. Feb 3, 2009

### yoleven

Looks okay.
I used this:
V$$_{f}$$=V$$_{i}$$+at

velocity at the highest point is 0, so..

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