Question

A 10,000kg truck traveling 5m/s collides with a 1,500 kg Volkswagen traveling in the opposite direction at 14 m/s after the collision the truck and Volkswagen stick together. A) what is the final speed and direction of the mess immediately after the collision? (don't foget to define a positative direction) B) how much energery was lost?(heat, sound, vibrations and other etc) during the collision. (Hint calculate the KE of each vechile before and after the collision.

Answer 1

A. m1*V-m2*V2 = 10,000*5-1,500*14=29,000

m1*V+m2*V = 29,000
10,000*V + 1500*V = 29000
11,500V = 29000
V = 2.52 m/s. In the direction of the
truck.

B. KE1 = 0.5m1*V1^2 = 0.5*10,000*5^2 =
125,000 J. = 125 kJ. Before collision.

KE1 = 0.5*m1*V^2 = 0.5*10,000*2.52^2 = 31,752 J. = 31.75 kJ. After collision.

125-31.75 = 93.25 kJ. Lost during collision.


KE2 = 0.5*m2*V2^2 = 0.5*1500*14^2 = 147000 J. = 147 kJ. Before collision.

KE2 = 0.5m*V^2 = 0.5*1500*2.52^2 = 4763 J. = 4.763 kJ. After collision.

147 - 4.763 = 142 kJ. Lost during collision.


93.25kJ + 142kJ = 235 kJ = KE lost
during collision.