Question

A cannonball is launched from the ground at an angle of 30 degrees above the horizontal and a speed of 30 m/s. Ideally (no air resistance) the ball will land on the ground with a speed of

Answer 1

As we know that here no air resistance while ball is moving in air

So here we will say that

initial total energy = final total energy

$KE_i + U_i = KE_f + U_f$

here we know that

$Ui = U_f = 0$ (as it will be on ground at initial and final position)

so we will say

$KE_i = KE_f$

since mass is always conserved

so we will say that final speed of the ball must be equal to the initial speed of the ball

so we have

$v_f = v_i = 30 m/s$