the scientific study of natural forces such as light, sound, heat, electricity, pressure, etc.
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.
Answer:
D
friction acts in the opposite direction of motion but does not affect the motion of the object
Answer:
The observer sees the space-probe 9.055m long.
Explanation:
Let 
be the length of the space-probe when measured at rest, and 
be its length as observed by an observer moving at velocity 
, then
Now, we know that 
and 
, and putting these into 
we get:
Thus, an observer moving at 0.95c observes the space-probe to be 9.055m long.
