Respuesta :
Two pucks moving on a frictionless air table are about to collide, as shown. The 1.5 kg puck is movingdirectly east at 2.0 m/s. Two objects of mass 0.2 kg and 0.1 kg, respectively, move parallel to the x-axis,as shown on Immediately after the collision, the y-component of the velocity of the 0.2 kg object is 1 m/s upward.
Answer: the velocity in the y component is -2m/s
Explanation: Here we must apply the conservation of the linear momentum.
In the initial scenario, both objects move in the x-direction, so the total momentum in y is equal to zero because momentum is Py = m*vy
In this scenario, we only have momentum in x, but that does not matter in this problem.
Now, after the collision, the object of m = 0.2kg, has a velocity in y of vy1 = 1m/s, then the momentum of this object is Py1 = 0.2kg*1m/s = 0.2kg*m/s
Now we apply the conservation, before the impact we have that the total momentum in y is zero, so we have now that:
Py1 + Py2 = 0 = 0.2kg*m/s + Py2
and Py2 = 0.1kg*vy2
0.1kg*vy2 = 0.2kg*m/s
vy1 = -(0.2kg*m/s)/(0.1kg) = -2m/s