3. A 231-g model-train car traveling at 0.52 m/s heads toward a 384-g car that i

Question

3. A 231-g model-train car traveling at 0.52 m/s heads toward a 384-g car that is initially at rest. (a) Find the total kinetic energy of the two-car system. 0.033996 X 3 (b) Find the velocity of each car in the center-of-mass reference frame. 231-g model-train m/s 384-g car m/s Use these velocities to calculate the kinetic energy of the two-car system in the center-of-mass reference frame. mJ (c) Find the kinetic energy associated with the motion of the center of mass of the system. mJ (d) Compare your answer for Part (a) with the sum of your answers for Parts (b) and (c). (Do this on paper. Your instructor may ask you to turn in this work.) Let the system include Earth and the cars. You can use conservation of momentum to find their speed after they have linked together and the definition of kinetic energy to find their pre- and post-collision kinetic 4. A block and a gun are firmly affixed to opposite ends of a long glider mounted on a frictionless air track. The block and gun are a distance L apart. The system is initially at rest. The gun is fired and the bullet leaves the muzzle with a velocity vb (relative to the fixed air track) and impacts on the block, becoming embedded in it. The mass of

Explanation / Answer

kE of car1 = 0.5 mv^2 = 0.5 * 0.231 * 0.52* 0.52 = 0.0312 J

KE of car 2 = 0.5 mv^2 = 0 J

total KE two car system = 0.0312 + 0 = 0.0312 J = 31.2 mJ

---------------------------------

part B :

final velocity of car1 = V1 = 2m2u1/(m1+m2)

v1 = 2 * 0.384 * 0.52/(0.231+ 0.384)

v1 = 0.65 m/s

KEf1 = 0.5 *0.231 * 0.65^2 = 48.7 mJ

V2 = (m2-m1)u1/(m2+m1)

V2 = (0.384-0.231)* 0.52/(0.384 + 0.231)

v2 = 0.129 m/s

KEf2 = 0.5* 0.384* 0.129^2 = 3.2 mJ

------------------------------------

total final KE = (0.5* 0.231* 0.65^2) + (0.5 * 0.384*.129^2)

fina KE = 0.052 J = 52 mJ

-----------------------

No energy is not conserved

Related Questions

Navigate

• Browse (All)
• Browse 3
• Subjects

---

---

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