- Use equations of motion under constant acceleration (gravity). - Define a consistent coordinate system (origin and positive direction). - Set the positions of the two objects equal to find the time of collision. - Use the time of collision to find the position (height) of collision.
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?
Asked in UPSC NDA 2 2016 · Topic: Motion under Gravity (Vertical motion: upward and downward projection of objects)
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Answer: C. The balls will collide after 1s at a height of 15·1 m from the ground
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