Question

Finding final velocity?

A canoeist on a lake throws a 0.145 kg baseball at 20.0 m/s to a friend in a different canoe. Each canoe with its contents has a mass of 120 kg, and is at rest initially. How fast is the first canoe moving after the pitch, assuming no friction with the water?

I believe the answer is 0.024 m/s, can anyone confirm this?

Answer 1

@Euler271 ?? I think I've seen your posts before, and you seem very helpful!

Answer 2

@austinL ?
Sorry if I'm not using these right. I'm new to the forum!

Answer 3

use conservation on momentum (linear)

Answer 4

of*

Answer 5

What is the formula again?

Answer 6

p=mv

Answer 7

20 * 0.145?

Answer 8

that will give you the momentum of the ball, yes

Answer 9

And then I use a different formula, I think... M1V1 + M2V2 = Vf (m1+m2)?

Answer 10

or just use the now known momentum to calculate what velocity the boat will have

Answer 11

since the momentum from the ball will be gained by the boat when the guy catches it

Answer 12

Oh, so I use the formula for velocity! I think that's what you're saying.

Answer 13

so the ball has momentum equal to

\[p=0.145kg*20m/s= 2.9 N*s\]

This momentum will be transfered to the boat due to the conservation on linear momentum as so

\[2.9N*s = 120kg*v\]

now solve for the velocity, no need to use the kinematic eq's

Answer 14

41 m/s?

Answer 15

\[2.9N*s/120kg = 0.2416 m/s\]

Answer 16

OH, I see!! Thank you so much!!!

Answer 17

yvw