Physics
posted by James .
A sled that has a mass of 8.8kg moves horizontally at 20 km/h. When it passes under a bridge 13kg of snow drops ontothe sled. What is its subsequent speed?
Isn't this in inellastic collision equation. I used (m1v1)+(m2v2)=(m1+m2)(vf)
m1=8.8kg
v1=20km/h
m2=21.8kg
v2=0km/h
I got 5.75 km/h where did i go wrong?

You went wrong doing the math. The equation you wrote is correct. m2 = 13, not 21.8.
(8.8)(20) = 21.8 Vf
Vf = 8.1 m/s