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Question:

A projectile is fired from the surface of the earth with a velocity of 5 ms⁻¹ and angle 8° with the horizontal. Another projectile fired from another planet with a velocity of 3 ms⁻¹ at the same angle follows a trajectory which is identical with the trajectory of the projectile fired from the earth. The value of the acceleration due to gravity on the planet is: (given g = 9.8 ms⁻²)

3.5

16.3

5.9

110.8

Solution:

For same trajectory both should have same horizontal range and maximum heights
=> 5²/g = 3²/a
=> a = 9.8 × 9/25
a = 3.5