Answer:
Mass is how much space the object takes up and how much it has inside, and weight is how heavy the object is.
Explanation: Hope this helps ;)
It should be at the very top since it has more space to fall which gives it more potential energy
Answers:
1) 
2) 
Explanation:
1) Acceleration 
is defined as the variation of Velocity 
in time 
:
(1)
A body also has acceleration when it changes its direction.
In this case we have a bus with a velocity of 60m/s to the east, that accelerates in a time 10s. So, we have to find the bus's acceleration:
(2)
(3) This is the bus's accelerration
2) Now we have a car that accelerates 
to the west in order to reach a speed of 
in the same direction, and we have to find the time it takes to the car to reach that velocity.
Therefore we have to find from (1):
(4)
(5)
Finally:
(6)
There are at least two forces on it, and there could be more.
Vertical forces:
-- gravity, directed downward
-- buoyant force, directed upward
These two forces must be exactly equal, so that the net
vertical force on the raft is zero. Otherwise, it would be
accelerating either up or down.
Horizontal forces:
We know that the net horizontal force on the raft is zero.
Otherwise, it would be accelerating horizontally.
But we don't know if there are actually no horizontal forces
at all, or a balanced group of horizontal forces, that add up
to a net force of zero.
