A 2.0-kg projectile is fired with initial velocity components vox = 30 m/s and voy = 40 m/s from a point on the earth's surface. Neglect any effects due to air resistance.
-What is the kinetic energy of the projectile when it reaches the highest point in its trajectory?
A)zero joules
B)900 J
C)1600 J
D)2500 J
E)4900 J

Question

Quizplus · Accepted Answer

At the highest point in the projectile's trajectory, its vertical velocity component (voy) is zero. Therefore, its total velocity is given by v = vox, and its kinetic energy is given by KE = (1/2)m*v^2 = (1/2)*2.0 kg*(30 m/s)^2 = 900 J.

A 20-Kg Projectile Is Fired with Initial Velocity Components Vox =