Wednesday
May 4, 2016

Homework Help: Physics

Posted by Jon on Monday, November 9, 2009 at 10:40am.

A child throws a snowball at a tree and it sticks to the tree. Does this motion defy the Law of Conservation of Momentum? Explain.

I'm thinking yes.
Given that p(momentum)= mass x velocity, even though the tree is stationary, it would have a much greater momentum due to it's mass than the nearly weightless snowball even though it is in motion. Because the tree has greater momentum than the snowball, the snowball would not be able to change the motion of the tree (rest).

Am i correct? Is there a better way to explain this? Any suggestions?
Thanks
• Physics - Jordan, Monday, November 9, 2009 at 11:03am

saying that the tree is stationary would give it a velocity of 0 therefor meaning it has no momentum as mass x 0 = 0
that sort of disproves your whole explanation

think about the question too, what does the Law of Conservation of Momentum say? think about what a law is, can you defy the law of gravity and just start floating?

• Physics - bobpursley, Monday, November 9, 2009 at 11:42am

The tree is connected to the Earth. The Earth moves in reaction, very little admittedly, but it does react to the snowball. Actually, when the snowball was thrown, it reacted in the opposite direction to the throwing also.

• Physics - Jon, Monday, November 9, 2009 at 10:26pm

my bad.. i did not see the 'defy part' !