Why do we feel dizzy when riding a giant wheel (Ferris wheel) rotating in a vertical plane?

Two trolleys $A$ and $B$ are moving with accelerations $a$ and $2a$ respectively in the same direction. To an observer in trolley $A$,the magnitude of the pseudo force acting on a block of mass $m$ on trolley $B$ is

$A$ ball is dropped from an elevator moving upward with acceleration '$a$' by a boy standing in it. What is the acceleration of the ball with respect to the boy and the ground respectively? [Take upward direction as positive]

$A$ rough vertical board has an acceleration $a$ so that a $2 \ kg$ block pressing against it does not fall. The coefficient of friction between the block and the board should be

The apparent weight of a girl of mass $30 \ kg$ when she is in a lift moving vertically upwards with an acceleration of $2 \ m \ s^{-2}$ is (Acceleration due to gravity $= 10 \ m \ s^{-2}$) (in $N$)

$A$ trolley is sliding freely down an inclined plane as shown in the figure. The angle $(\alpha)$ that the string of the pendulum makes with the ceiling of the trolley is equal to ..........