Please answer the following and please show work. Thanks A 1 125.0 kg car travel
ID: 2039043 • Letter: P
Question
Please answer the following and please show work. Thanks
A 1 125.0 kg car traveling initially with a speed of 25.000 m/s in an easterly direction crashes into the back of a 9 800.0 kg truck moving in the same direction at 20.000 m/s. The velocity of the car right after the collision is 18.000 m/s to the east. VT Cf Before After (a) What is the velocity of the truck right after the collision? (Give your answer to five significant figures.) m/s east (b) What is the change in mechanical energy of the car-truck system in the collision The response you submitted has the wrong sign.Explanation / Answer
here,
mass of car , m1 = 1125 kg
mass of truck , m2 = 9800 kg
initial speed of car , u1 = 25 m/s
initial speed of truck , u2 = 20 m/s
final speed of car , v1 = 18 m/s
let the final speed of truck be v2
using conservation of momentum
m1 * u1 + m2 * u2 = m1 * v1 + m2 * v2
1125 * 25 + 9800 * 20 = 1125 * 18 + 9800 * v2
solving for v2
v2 = 20.8 m/s
the final speed of truck is 20.8 m/s
b)
the change in mechanical energy , ME = 0.5 * m1 * v1^2 + 0.5 * m2 * v2^2 - 0.5 * m1 * u1^2 -0.5 * m2 * u2^2
ME = 0.5 * ( 1125 * 18^2 + 9800 * 20.8^2 - 1125 * 25^2 - 9800 * 20^2) J
ME = - 9376.5 J