$A$ block is lying at rest inside a bus. What is the maximum acceleration of the bus such that the block remains stationary? (The static friction coefficient $\mu = 0.2$,acceleration due to gravity $g = 10 \ m/s^2$)

$A$ car is moving with a uniform speed on a level road. Inside the car,there is a balloon filled with helium and attached to a piece of string tied to the floor. The string is observed to be vertical. The car now takes a left turn while maintaining the same speed on the level road. The balloon in the car will:

Imagine a person standing on a weighing machine placed inside an elevator. The elevator first accelerates, then moves with a constant velocity, and finally decelerates to stop. The maximum and minimum weight recorded are $80 \ kg$ and $64 \ kg$, respectively. Find out the true mass of that person considering $g = 10 \ m/s^2$. (in $kg$)

$A$ man of weight $W$ is standing on a lift which is moving downward with an acceleration $a$. The apparent weight of the man is

$A$ ball is suspended on a thread from the ceiling of a car. The brakes are applied and the speed of the car changes from $5\, m/s$ to $\frac{5}{3}\, m/s$ during the time interval of $3\, s$. The angle that the thread will deviate from the vertical in the new equilibrium position is:

$A$ 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 ......... $kg$.