In elastic collision case, kinetic energy is: Conserved Not conserved Energy con
ID: 1509359 • Letter: I
Question
In elastic collision case, kinetic energy is: Conserved Not conserved Energy conservation depends on the object's mass Energy conservation depends on the object's velocity There is no kinetic energy in elastic collision In inelastic collision case, kinetic energy is Conserved Not conserved c) Energy conservation depends on the object's mass Energy conservation depends on the object's velocity There is no kinetic energy in inelastic collision A 8.00-kg mass moving at 20.00m/s collides with a 4.00-kg mass moving at 14m/s in the opposite direction. The masses stick together after collision. What is the difference in kinetic energy before and after collision? What is the difference in momentum before and after collision? What kind of collision (elastic or inelastic) it is? If two masses after collision don't stick together, what kind of collision (elastic or inelastic) it is?Explanation / Answer
4) m1 =8 kg, m2 = 4 kg, u1 =20 m/s, u2 = -14 m/s
(a) from conservation of momentum
m1u1 +m2u2 = (m1+m2)v
(8*20) - (4*14) = (8+4)v
v = 8.67 m/s
K1 -K2 = (1/2)m1u1^2 +(1/2)m2u2^2 -(1/2)(m1+m2)v^2
= (0.5*8*20*20) +(0.5*4*14*14) - (0.5*12*8.67*8.67)
= 1541 J
(b) zero
(c) inelastic collision
(d) elastic