Question

suzy stands on the talahatchee bridge kicking stones into the water below. if she kicks a stone with a horizontal velocity of 3.50 m/s, and it lands in the water a horizontal distance if 5.40 m from where she is standing, how high is the bridge. can you help me thus us 2-d motion

Answer 1

Yep. I think I can.

Horizontal motion doesn't speed up or slow down.

distance = (speed) x (time)

5.4 m = (3.5 m/s) x (time)
Divide each side
by 3.5 m/s: (5.4 m) / (3.5 m/s) = time

time = 1.543 seconds (rounded) .

That's how much time the stone took to fall from the bridge to the water.

Now we can go on to the vertical distance:
Do you remember this physics formula for falling distance ?

Distance = (1/2) (gravity) (time)²

Distance = (1/2) (9.8 m/s²) (1.543 sec)²

= (4.9 m/s²) x (2.38 sec²)

= 11.7 meters .