$A$ block of mass $m$ is resting on a wedge of angle $\theta$ as shown in the figure. The wedge is given a horizontal acceleration $a$. What is the minimum value of $a$ so that the mass $m$ falls freely?

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

$A$ body of mass $2 \, kg$ is hung on a spring balance mounted vertically in a lift. If the lift descends with an acceleration equal to the acceleration due to gravity $g$,the reading on the spring balance will be ....... $kg$.

$A$ body of mass $2 \, kg$ is hung on a spring balance mounted vertically in a lift. If the lift descends with an acceleration equal to the acceleration due to gravity $g$,and if the lift moves up with a constant velocity of $2 \, m/s$,the reading on the balance will be ......... $kg$.

$A$ body of mass $4 \, kg$ weighs $4.8 \, kg$ when suspended in a moving lift. The acceleration of the lift is

Two blocks of masses $2 \,kg$ and $4 \,kg$ are hanging with the help of a massless string passing over an ideal pulley inside an elevator. The elevator is moving upward with an acceleration $\frac{g}{2}$. The tension in the string connected between the blocks will be .......... $N$ (Take $g=10 \,m/s^2$).