Walking to school. Hope this helps!
Answer:
it change speed
Explanation:
its because when light passes through one medium to another (rarer to denser)its velocity change and its speed also changes
Yeah oppp because this is yes
Physical: the raft needs to float, which means what you make the raft out of must be less dense than water.
The raft would need sturdiness- if the raft is frail, the water might break it
Chemical: It can not react with water and it can not be made of a completely soluable substance (something that would dissolve in it like salt)
Your answer for part a is correct. Using Newton's 3rd Law, the force on the rocket by the exhaust leaving the rocket is the same magnitude (opposite direction) as the downward force applied to the exhaust.
In part b the net force is the upward force from the exhaust thrust minus the downward force of gravity:

Then using the Second Law, we get for part c:

The force and acceleration are in the upward direction