The trajectory of a projectile projected from the ground is given by y = x - x²/20, where x and y are measured in metres. The maximum height attained by the projectile is:
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Question

The trajectory of a projectile projected from the ground is given by y = x - x²/20, where x and y are measured in metres. The maximum height attained by the projectile is:

G1 Physics · Accepted Answer

Given trajectory: y = x - x²/20 For maximum height, dy/dx = 0 Now, dy/dx = 1 - x/10 So, 1 - x/10 = 0 x = 10 m Substitute x = 10 m: y(max) = 10 - 10²/20 = 10 - 100/20 = 10 - 5 = 5 m Hence option D follows.