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  • Smart Learning for All

  • Topic: Newton's First Law of Motion.

  • Why do you fall backwards when a bus starts suddenly?

  • Did you observe that the bag fell when brakes were applied?

  • Do you know why this happened?

  • This happened because of inertia.

  • Inertia is the tendency of a body to be in a state of rest or in a state of motion.

  • Newton's first law of motion defines inertia.

  • It states that a body in rest stays in rest and a body in motion stays in motion.

  • Unless it is acted upon by an external force.

  • So, in this case, when the bag was on the bike, it was moving along with the bike.

  • Now, when brakes were applied suddenly.

  • The bike stopped but the bag kept on moving forward due to inertia of motion and hence it fell.

  • This time the bag fell again.

  • Can you guess why?

  • Yes, you guessed it right.

  • It is also because of inertia.

  • When the bag was on the stationary bike, it was at rest.

  • Now, when the bike was accelerated suddenly, it moved forward.

  • But the bag being at rest, did not move due to inertia of rest and hence it fell down again.

  • In this case, when the bus suddenly starts moving forward.

  • Our feet which are in contact with the bus start moving forward.

  • As a result, the lower part of our body moves forward.

  • But the upper part of our body, which is not in contact with the bus still tends to remain in a state of rest.

  • The upper part of the body does not move forward along the lower part.

  • That is why we tend to fall backwards.

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Smart Learning for All

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