Question Detail
Question
A 1 kg ball is fired from a cannon directly upwards in an airless chamber. Its initial speed is 10 m/s, and it reaches a height of 5 m before falling due to Earth's gravity. If a 2 kg ball is fired at 20 m/s directly upwards, what height will it reach before it begins falling, rounded to the nearest meter? Acceleration due to gravity is 10 m/s².
Correct Answer
Option D is the correct answer.
Detailed Explanation
Maximum height for a projectile launched vertically is given by H = u²/(2g). For the second ball, u = 20 m/s, g = 10 m/s², so H = (20)²/(2×10) = 400/20 = 20 m. The mass does not affect the height in the absence of air resistance.
Hint
Use the formula for maximum height in vertical motion under constant gravity.