Question

The distance travelled by a body during last second of its total flight is d when the body projected vertically up with certain velocity If the velocity of projection is doubled, the distance travelled by the body during last second of its total flight is (1) 2d (2) d​

Answer 1

Answer:

2d + g/2

Explanation:

The distance travelled by a body during last second of its total flight is d when the body projected vertically up with certain velocity If the velocity of projection is doubled, the distance travelled by the body during last second of its total flight is

Body Thrown Vertically with Velocity V

Return With Velocity V

Velocity 1 sec  before  =  V - g

Distance Traveled in 1 sec

V²  - (V-g)² = 2gd

=> V² - (V² + g² -2gV) = 2gd

=>  2gV - g² = 2gd

=>  V - g/2 = d

When Thrown With Velocity 2V

Return With Velocity 2V

Velocity 1 sec  before  =  2V - g

Distance Traveled in 1 sec

(2V)²  - (2V-g)² = 2gS

=> 4V² - (4V² + g² -4gV) = 2gS

=>  4gV - g² = 2gS

=>  2V - g/2 = S

=> S = 2(V - g/2) + g/2

=> S = 2d + g/2