- #1

Newlander

- 6

- 0

## Homework Statement

"A boy throws a rock with an initial velocity of 3.13 m/s at 30.0 degrees above the horizontal. How long does it take for the rock to reach the maximum height of its trajectory?"

v

_{i}= 3.13 m/s

t

_{max height}= ?

v

_{f}= 0 m/s (at max height)

a = -9.8 m/s

^{2}

## Homework Equations

v

_{f}= v

_{i}+ at

(Not sure!)

## The Attempt at a Solution

v

_{f}= v

_{i}+ at

t = [(v

_{f}- v

_{i}) / a] = [(0 m/s - 3.13 m/s)/-9.8 m/s

^{2}]

t = 0.319 s

Concern:

The correct answer is listed as 0.313 s; because my answer is so close, I wondered if this were a typo. If not, I clearly am taking the wrong approach and would appreciate some guidance.