Laws of Motion

A person sitting inside an elevator performs a weighing experiment with an object of mass 50 kg. Suppose that the variation of the height y (in m) of the elevator, from the ground, with time t (in s) is given by y=8 [1+ ( 2 tT ) ], where T=40 s. Taking acceleration due to gravity, g=10 m/s2, the maximum variation of the object's weight (in N) as observed in the experiment is

A projectile of mass 200 g is launched in a viscous medium at an angle 60 with the horizontal, with an initial velocity of 270 m/s. It experiences a viscous drag force F=-c v where the drag coefficient c=0.1 kg/s and v is the instantaneous velocity of the projectile. The projectile hits a vertical wall after 2 s. Taking e=2.7, the horizontal distance of the wall from the point of projection (in m) is