SCIENCE
PHYSICAL SCIENCES
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Acceleration towards the Earth as an object falls.
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Slowing down while moving in the negative direction.
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Speeding up while moving in the positive direction.
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Acceleration of an object thrown upwards from the surface of the Earth with an initial velocity of 8m s-1.
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Detailed explanation-1: -Its acceleration is −9.8 ms−2 at the very top since the body is moving upward against the gravity. In other words, the acceleration due to gravity g=9.8 ms−2↓.
Detailed explanation-2: -Since the acceleration moves the ball up against the force of gravity, it is negative. Thus the option (A) is correct. Note: Let us consider one example of this case.
Detailed explanation-3: -Answer: 0 m/s. The instantaneous speed of any projectile at its maximum height is zero. Because gravity provides the same acceleration to the ball on the way up (slowing it down) as on the way down (speeding it up), the time to reach maximum altitude is the same as the time to return to its launch position.
Detailed explanation-4: -When an object is thrown vertically upwards, the acceleration due to gravity remains unchanged and acts in downward direction. Since the axis was chosen such that positive is the upward direction, acceleration due to gravity is negative. Q.