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A 0.6- kg toy truck moving at an initial speed of 0.3 m/scollides head-on with a

ID: 1682515 • Letter: A

Question

A 0.6- kg toy truck moving at an initial speed of 0.3 m/scollides head-on with a 0.2- kg toy car at rest. The collision isperfectly inelastic, so the two toys stick together.
Find their final speed. Calculate how much kinetic energy was lost in thecollision. A 0.6- kg toy truck moving at an initial speed of 0.3 m/scollides head-on with a 0.2- kg toy car at rest. The collision isperfectly inelastic, so the two toys stick together.
Find their final speed. Calculate how much kinetic energy was lost in thecollision.

Explanation / Answer

Use conservation of momentum: Before momentum = 0.6 * 0.3 = 0.18 kgm/s After momentum = (0.6+0.2)*v where v is the final speed. By conservation of momentum: (0.6+0.2)*v = 0.18 Hence v = 0.18/0.8 = 0.225 m/s Kinetic energy before collision = (1/2)mv2 =(1/2)*0.6*0.32 = 0.027 J Kinetic energy after collision = (1/2)*(0.6+0.2)*0.2252= 0.02025 J So KE lost = 0.027 - 0.02025 = 0.00675 J