Answer to Question #192055 in Mechanics | Relativity for Nicole

Question

Ballistics experts are testing projectiles. Projectile A has mass m and is fired with a velocity 2v. Projectile B has mass 2m and is fired with velocity v. Projectile C has mass m and is fired at a speed v. Which projectile has the greatest kinetic energy?

(A) Projectile A

(B) Projectile B

(C) Projectile C

(D) Both A and B have equal kinetic energy

Answer 1

$K.E =1/2mv^2$

for A, $K.E=1/2m(2v)^2=2mv^2$

for B, $K.E=1/2\times2m\times v^2=mv^2$

for C, $K.E=1/2mv^2=0.5mv^2$

thus A has the greatest kinetic energy