An 1446 kg car stopped at a traffic light is struck from the rear by a 840 kg ca

Question

An 1446 kg car stopped at a traffic light is struck from the rear by a 840 kg car and the two become entangled. If the smaller car was moving at 29.5 m/s before the collision, what is the speed of the entangled cars after the collision?

(a) What is the loss of kinetic energy (Ki - Kf) in the situation described in the example.

231 kJ

(b) What if the 840 kg car actually moves backwards with a speed of 2.4 m/s right after the collision instead of having a perfectly elastic collision. What is the velocity of the heavier car immediately after the collision? Use the same convention for positive direction as defined in the example.

18.5m/s

(c) What is the loss of kinetic energy in this case?

_______ kJ
From the result in (b), what is the initial and final kinetic energies of the system?

_________________

QUESTION 2

2) Suppose m1 = 7.7 kg, m2 = 11.26 kg and vf = 5.99 m/s. If v1i = 10.2 m/s, what was v2i?

Explanation / Answer

C) Loss of Kinetic energy = (0.5*840*29.5^2) - (0.5*1446*18.5^2 + 0.5*840*2.4^2) = 365505 - (247446.75 + 2419.2) = 365505 - 249865.95 =115639.05 J ( ans)

D) initial ke = 365505 J (ans)

Final ke = 249865.05 J ( ans)

2) momentum conservation

7.7*10.2 +11.26*v2i = 18.96*5.99

V2i = 3.11 m/sec (ans)

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.