<h3><u>
Answer:</u></h3>
When it was first made, it was heavier
<h3><u>
Explanation:</u></h3>
So there was originally air in the Ice Cream because they fluff it up like that. When it melts, those are gone.
Answer:
gravitational potential energy
The block moves with constant velocity: for Newton's second law, this means that the resultant of the forces acting on the block is zero, because the acceleration is zero.
We are only concerned about the horizontal direction, and there are only two forces acting along this direction: the force F pushing the block and the frictional force

acting against the motion. Since their resultant must be zero, we have:

The frictional force is

where

is the coefficient of kinetic friction

is the weight of the block.
Substituting these values, we find the magnitude of the force F:
Answer:
Explanation:
For this problem, we just need to remember conservation of momentum, as there are no external forces in the horizontal direction:

where the suffix i means initial, and the suffix f means final.
The initial momentum will be:

as the second puck is initially at rest:

Using the unit vector
pointing in the original line of motion:



So:


Knowing the magnitude and directions relative to the x axis, we can find Cartesian representation of the vectors using the formula

So, our velocity vectors will be:


We got


So, we got the equations:

and
.
From the last one, we get:




and, for the first one:






so:

and

