An object of mass 5 kg is thrown vertically upwards from the ground. The air resistance produces a constant retarding force of 10 N throughout the motion. The ratio of time of ascent to the time of descent will be equal to : [Use g = 10 m s - 2 ].

Step-by-step solution

Net force while going upward will be m g + R = 50 + 10 = 60   N ⇒ a u p = 60 5 = 12   m   s - 2 Similarly, Net force while going downward will be m g - R = 40   N ⇒ a d = 40 5 = 8   m   s - 2 Since h = 1 2 a t 2 ⇒ a u p t u p 2 a d t d 2 = 1 ⇒ t u p t d = 8 12 = 2 3