A toy car (A) weighing 309.7 grams is pushed and collides with a stationary toy

Question

A toy car (A) weighing 309.7 grams is pushed and collides with a stationary toy car (B) weighing 507.1 grams at an initial speed of 76.598 m/s. The cars collied and bounce off eachother. The speed of the stationary car (B) is pushed back at a speed of 45.6 m/s. The recoiled speed of car A, after is hits car B, is 18.575 m/s.

Calculate the kinetic energies of the cars. I need to find the KE1i, KE1f, KE2f, and the total initial kinetic energy and the total final kinetic energy. Please help. I'm very confused on this part. I was using 1/2 mv2 =k to find KE1i, KE1f, and KE2f. To find the initial and final I'm using 1/2mvf2 - 1/2 mvi2. I'm not postive if this is correct, because I'm getting very high numbers. I may not be using the equation correctly.

Explanation / Answer

ma = 309.7 g = 0.3097 kg

mb = 507.1 g = 0.5071 g

Vai = 76.598 m/s

Vbi = 0 m/s

Vaf = - 18.575 m/s

Vbf = 45.6 m/s

KEai = (0.5) ma Vai2 = (0.5) (0.3097) (76.598)2 J = 908.54 J

KEbi = (0.5) mb Vbi2 = (0.5) (0.5071) (0)2 J = 0 J

KEaf = (0.5) ma Vaf2 = (0.5) (0.3097) (-18.575)2 J = 53.428 J

KEbf = (0.5) mb Vbf2 = (0.5) (0.5071) (45.6)2 J = 527.22 J

Total initial Kinetic energy = 908.54 J

Total final Kinetic energy = 527.22 + 53.428 = 580.65 J

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

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