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A stone thrown vertically upwards went up 98 m and came down. How long was it in the air? |
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Answer» Final Velocity of stone,v=0 because after ATTAINING the maximum HEIGHT it will come at rest and begin to fall down.Initial velocity,u=98m/sAcceleration due to GRAVITY,a= -9.8 m/s because the motion of ball is OPPOSITE to the direction of the ACCELERATION caused due to gravity.∴ Using first kinematical equation, we getv = u + at0=98+(-9.8)t-98= -9.8t∴ t = -98/-9.8∴ t=10 secondsBy using second kinematical equation, we gets = ut + 1/2 at^2∴ s = 98*10 + 1/2 *(-9.8)*10*10∴ s = 980 + 1/2 * (-980)∴ s = 980 + (-490)∴ s = 490 mHope it helps |
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