Physics
In a supermarket, Avantika could easily push an empty trolley but found it difficult to push a trolley full of groceries. The loaded trolley accelerated very slowly even when the same force was applied. To keep the trolley moving, she had to apply a greater force.
(a) Why did the loaded trolley accelerate less?
(b) According to you, which law of motion explains this observation?
(c) Why did Avantika have to apply a greater force to the loaded trolley?
(d) Correlate this event with one other similar example from daily life.
Laws of Motion
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Answer
(a) The loaded trolley accelerated less because it had greater mass and according to the relation F = ma, for the same applied force, a body with larger mass has smaller acceleration. Therefore, the trolley full of groceries moved more slowly.
(b) Newton's Second Law of Motion explains this observation. It states that acceleration is directly proportional to the applied force and inversely proportional to the mass of the body.
(c) Avantika had to apply greater force because the loaded trolley had greater mass and hence greater inertia. Therefore, more force was needed to change its state of motion or to produce the required acceleration.
(d) A similar example from daily life is that it is easier to kick an empty football than a heavy stone, because the stone has greater mass and needs more force to change its motion.
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