The initial kinetic energy imparted to a

0.72 kg bullet is 1777 J. The acceleration of gravity is 9.81m/s2.Neglecting air resistance, find the range of this projectile when it is fired at an angle such that the range equals the maximum height attained.
Answer in units of km.

1 answer

First calculate the initial velocity Vo, using
(M/2)Vo^2 = 1777 J

If the range equals the maximum height,
2(Vo^2/g)sinA*cosA = (1/2)(Vo^2/g)sin^2A

2 cosA = (1/2)sin A
tanA = 4 A = 76.0 degrees
Use that angle in either the range or the max height formula