$A$ man weighing $60 \text{ kg}$ is in a lift moving down with an acceleration of $1.8 \text{ ms}^{-2}$. The force exerted by the floor on him is:

$A$ 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 ..........

You stand on a spring scale on the floor of an elevator. Of the following,the scale shows the highest reading when the elevator

The free surface of oil in a tanker,at rest,is horizontal. If the tanker starts accelerating,the free surface will be tilted by an angle $\theta$. If the acceleration is $a \ m/s^2$,what will be the slope of the free surface?

$A$ cork is submerged in water by a spring attached to the bottom of a bowl. When the bowl is kept in an elevator moving with an acceleration $a$ downwards, the length of the spring:

The weight of a man in a lift moving upward is $608 \ N$,while the weight of the same man in the lift moving downward with the same acceleration is $368 \ N$. His normal weight is ............ $N$.