# Homework Help: Kinematics problem: velocity of a falling object at a certain point with starting v?

1. Sep 29, 2009

### therest

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

A ball is thrown vertically upward with a speed of 25.2 m/s.
a)How high does it rise? Answer in units of m.
b) How long does it take to reach its highest point? Answer in units of s.
c) How long does it take the ball to hit the ground after it reaches its highest point? Answer in units of s.
d) What is its velocity when it returns to the level from which it started? Answer in units
of m/s.

2. Relevant equations
all kinematics equations.
I used x=x0 + v0t + (1/2)at^2, I remember.

3. The attempt at a solution
I have a thru c - a was 32.37, and b abd c were both 2.57 (parabola was symmetrical) but I have no idea how to solve d, at all.

2. Sep 29, 2009

### ryan88

Re: Kinematics problem: velocity of a falling object at a certain point with starting

Since the ball is taking the same time to rise as it is to fall again, this would mean that by the time the ball reached the same level it was as at when it started, it would be going the same speed as it was when it was first thrown upwards.