Two balls, A and B, are thrown simultaneously, a vertically upward with a speed of 20 m/s from the ground and B vertically downward from a height of 40 m with the same speed and along the same line of motion. At what points do the two balls collide by taking acceleration due to gravity as 9.8 m/s2?

• A. The balls will collide after 3s at a height of 30.2 m from the ground
• B. The balls will collide after 2s at a height of 20.1 m from the ground
• C. The balls will collide after 1s at a height of 15.1 m from the ground
• D. The balls will collide after 5s at a height of 20 m from the ground