Answer:
14.6m/s
Step-by-step explanation:
elastic collision formula
mv1+mv2=mv1'+mv2'
mv1= mass times velocity of the first object
mv2= mass times velocity of the second object
mv1'=mass times velocity of the first object after the collision
mv2= mass times velocity of the second object after the collision.
we know that the pin is not moving so we multiply 0 or its velocity by the mass 0.9kg this equals zero so we don't add this part to the equation.
mv1=mv1'+mv2'
plugin the values and solve using order of operations
12kg(2.4m/s)=12kg(1.3m/s)+0.9kg(v2')
28.8kg.m/s=15.6kg.m/s+0.9kg(v2')
at this point you need to move 15.6kg.m/s to the other side of the equation so subtract 15.6kg.m/s to 28.8kg.m/s
28.8kg.m/s=15.6kg.m/s+0.9kg(v2')
28.8kg.m/s - 15.6kg.m/s= 0.9kg(v2')
finally Divide by 0.9kg in order to leave v2' in one side.
13.2kg.m/s=0.9kg(v2')
13.2kg.m/s÷0.9kg=v2'
14.6kg.m/s=v2'