16. A uniform solid right circular cone of base radius R is joined to a uniform solid hemisphere of radius R and of the same density, so as to have a common face. The centre of mass of the composite solid lies on the common face. The height of the cone is : (a) 1.5 R (b) 3R (c) 3R (d) 23R 17. A lift is descending with a constant velocity 'v'. A man in the lift drops a coin. The coin experiences an acceleration towards the floor equal to : (a) g+v (b) g-v (c) g (d) zero 18. A ball is projected horizontal with a velocity of 5ms from the top of a building 20m. Displacement of ball when it hits the ground is : (g = 10m/s) (a) 10 m (b) 20 m (c) 103m (d) 105m 19. In which of the following cases the magnitude of acceleration of the block A will be maximum: (Neglect friction, mass of pulley and string) 20. m (a) 12m (c) m smooth A 2mg 2mg (b) m A (d) B2m A ball of mass 1 kg is connected with a L-shaped rod rotating with constant angular velocity = 10 rad/s through a light string CD. The length of part BC of the rod is 0.5 m. The length of string CD is: (g = 10 m/s) Shiksha (a) 0.5 m (b) m 22 (c) m (d) 2m