4. A 9000 kg train car travelling at 4.5 m/s inellastically collides with a 7500 kg train car at rest. If all of the kinetic energy not conserved in this collision goes into increasing the internal energy of
the cars, how many Joules were absorbed?

91125Joules

Explanation:

Given data

M1= 9000 kg

U1= 4.5m/s

M2= 7500 kg

U1= 0 m/s

KE1= 1/2M1U1^2

KE1= 1/2*9000*4.5^2

KE1= 1/2*9000*20.25

KE1= 1/2*182250

KE1=91125joules

KE2= 1/2M2U2^2

KE1= 1/2*7500*0^2

KE1=0 joules

Hence the energy absorbed is

E= KE1-KE2

E= 91125-0

E= 91125Joules

when insulating materials rub against each other, they may become electrically charged . electrons , which are negatively charged, may be 'rubbed off' one material and on to the other. the material that gains electrons becomes negatively charged. the material that loses electrons is left with a positive charge.

i think the answer is a and b

i wish you luck