250kg
would have momentum that is being caried by the impact of the trow
Answer:

Explanation:
Ok, the average speed can be calculate with the next equation:
(1)
Basically the car cover the same distance "d" two times, but at different speeds, so:

and the total time would be the time t1 required to go from A to B plus the time t2 required to go back from B to A:

From basic physics we know:

so:


Using the previous information in equation (1)

Factoring:
(2)
Finally, replacing the data in (2)

Reflecting telescope. Reflecting telescopes tend to have larger objective (due to the use of mirrors, mirrors are a lot cheaper than lenses) and have the ability to collect more light, while refracting telescopes are limited to objective lenses with smaller diameters due to their structural limitations (chromatic abbreviation, for example). Therefore, reflecting telescopes should be better at viewing faint distant stars
D When it is stretched ready to shoot at the wall
Answer:
25000 V
Explanation:
The formula for potential is
V = Kq/r
Potential at B due to the charge placed at origin O
V1 = K q / OB

V1 = 10000 V
Potential at B due to the charge placed at A
V2 = K q / AB

V2 = 15000 V
Total potential at B
V = V1 + V2 = 10000 + 15000 = 25000 V