Physics Questions

The interval between object pass the same point is 4 sec.

That means in 2 sec, object reaches the top and in next 2 sec, it again reaches the same point.

By the info given, we can find the velocity of that point by using : v=u+(-gt)

0= u - 10×2

u = 20

Then the velocity at 25m is 20m/sec.

so the initial velocity is

$$\begin{gathered} -v2 = u2 + (-2gh) \\ 400 = u2 - 2x 10 x 25 \\ u2 = 900 \\ => u = 30 m/s \end{gathered}$$

Velocitation is a phenomenon caused by driving for long periods at high speeds. A driver may experience velocitation when coming off of the highway; the change in speed makes him or her think that the car is going much slower than it actually is.

Velocitation is the tendency to be traveling at a speed that is faster than perceived.

The size of the pupil of the eye automatically adjusts itself  according to the intensity of light passing through it;if the intensity is more , the size is less, if less, it is more. So in our case the pupil should dilate i.e, increase in size to be able to see in the dark . This switchover takes sometime. But here the entry into the dark room is immediate . So the eye has no time to adjust itself and hence is not able to see at all for a while.