What is the common velocity of the arrow

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

An arrow of mass 100 g is fired with an initial horizontal velocity of 40 m s–1 to the right at an apple of mass 80 g that is initially at rest on a horizontal surface. When the arrow strikes the apple, the two objects stick together. What is the common velocity of the arrow and apple after the impact?

2. Relevant equations
Momentum = mass * velocity


3. The attempt at a solution

Initial Momentum of the Arrow
p=m*v
=(.1)(40)
= 4

4=.08* v
therefore v= 50 m/s

the answer says it's 22m/s
 

rl.bhat

Homework Helper
4,433
5
Re: Momentum

4=.08* v
therefore v= 50 m/s

This is wrong.
When the arrow strikes the apple, the two objects stick together.
So rewrite the above equation.
 
Re: Momentum

I don't get it
If the momentum is 0 then the velocity is 0
 

rl.bhat

Homework Helper
4,433
5
Re: Momentum

Momentum after impact = ( 0.1 + 0.08)*v
 
Re: Momentum

m1v1 = (m1 + m2)v
 

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