And here's another one. How fast must the receiver run?

1. Oct 5, 2007

pebbles

1. The problem statement, all variables and given/known data
A QB sees his receiver 25 m downfield and throws the ball to him at 45 degress, with speed 22 m/s

2. Relevant equations
well, speed=distance/total time, so i used the equation:d(y)=v(oy)t + .5a(y)t^2
parentheses indicate subscripts...

3. The attempt at a solution

t=-16m/s/-9.8m/s^2
total time=3.2 s.

But wait a second, do I have to account for the speed of the ball? Or can I now just do 25m/3.2s??

2. Oct 5, 2007

learningphysics

you have the time correct... but I'd be careful about your rounding...

What distance does the ball travel horizontally in this time?

What distance does the receiver need to travel to catch the ball?

3. Oct 5, 2007

pebbles

oops, 3.3 seconds

What distance does the ball travel horizontally in this time?
-22m/s * 3.3s?

What distance does the receiver need to travel to catch the ball?
-I'm guessing I would have to find where the ball would land, in which I have no idea how to calculate.

akldfjakldfjalkfjlkdajf. I'm exhausted.

4. Oct 5, 2007

learningphysics

What is the horizontal velocity of the ball?

Horizontal displacement of the ball is horizontal velocity * time.

I get time = 3.17s.