Car a hits car b (initially at rest and of equal mass) frombehind while going 35 m/s. immediately after the collision, car bmoves forward at 25 m/s and car a is at rest. what fraction of theinitial kinetic energy is lost in the collision?
my approach:
how exactly do you approach this question? at first, i thoughtusing the the formula σkei = σkef. then, to find the fraction just divide the former from the latter. but is it that cut and dry?
before collision:
via= 35 m/s
vib = 0 m/s
vfa = 0 m/s
vfb =25 m/s
m1 = m2

The fraction of kinetic energy lost in the collision in term of the initial energy is 0.49.

Explanation:

As the final and initial velocities are known it is possible then the kinetic energy is possible to calculate for each instant.

By definition, the kinetic energy is:

k = 0.5*mV^2

Expressing the initial and final kinetic energy for cars A and B:

Since the masses are equals:

For the known velocities, the kinetics energies result:

The lost energy in the collision is the difference between the initial and final kinectic energies:

Finally the relation between the lost and the initial kinetic energy:

i had this question and the answer was 3.15 miles.

martina travels from school to her mom's office. from there, she walks to school. after school, she walks to the library and then to a friends house before finally ending back at home. find martina's total distance traveled.

a) 0 miles  

b) 0.4 miles  

c) 1 mile  

d) 3.15 miles

find the sum of the two horizontal vectors and the sum of the two vertical vectors

isoceles right angled triangle