Answer:
Average speed = 0.0075 m/s
Average velocity = 0.0025 m/s along forward direction
Explanation:
Speed is the ratio of distance and time and velocity is the ratio of displacement and time.
Distance traveled = 10 + 5 = 15 cm = 0.15 m
Displacement = 10 - 5 = 5 cm = 0.05 m
Time = 20 seconds

Average speed = 0.0075 m/s
Average velocity = 0.0025 m/s along forward direction
It's a measure of the acceleration
Answer:
Electric field will be 
Explanation:
We have given potential difference between the two plates = 15000 volt
Distance between the plates = 
We have to find the electric field strength between the plates
Potential difference between the plates is equal to 
So electric field strength will be 
So electric field will be 
ASSUMING that the substance is a gas . . .
It all depends on HOW the pressure was increased.
-- IF the gas was left in the same container, and the pressure was increased by heating the container, then the volume hasn't changed. It's still the inside volume of the container.
-- IF the pressure was increased by stuffing all of the gas into a smaller container, then the new volume is the volume of the smaller container.
No matter what the mass or temperature of the gas is, it always expands to fill whatever container you're keeping it in.