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#final speed

9 public questions tagged with this topic.

A 9kg mass at 7m/s collides inelastically with a stationary 3kg mass. What is the final speed?

Momentum conservation: 9×7=(9+3)vf⇒63=12vf⇒vf=5.25m/s. As per NCERT Chapter 3, equations v=u+at, s=ut+½at², v²=u²+2as describe uniformly accelerated motion. Applying correct signs and units gives 5 m/s as the result, so option A is correct.

Ref: NCERT Class 11 Physics > Chapter 3: Motion in a Straight Line > Topic: Straight Line Motion - Practice Set0

A 11kg mass at 6m/s collides inelastically with a stationary 4kg mass. What is the final speed?

Momentum conservation: 11×6=(11+4)vf⇒66=15vf⇒vf=4.4m/s. As per NCERT Chapter 3, equations v=u+at, s=ut+½at², v²=u²+2as describe uniformly accelerated motion. Applying correct signs and units gives 4 m/s as the result, so option A is correct.

Ref: NCERT Class 11 Physics > Chapter 3: Motion in a Straight Line > Topic: Straight Line Motion - Practice Set0