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A particle is projected vertically upwards with velocity u from a point a when it returns to point of projection |
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Answer» Answer: H=ut-(1/2)gt^2. h=80m, g=10m/s^2. Then, t^2-(2/g)ut+(2/g)h=0. Solving, t={(2/g)u+_[(4/g^2)u^2–4(2/g)h]^(1/2)}/2 The difference between two roots is 6 [(1/25)u^2–64]^1/2=6. SQUARING (1/25)u^2–64=36 u^2=2500 or u=50m/s^2. Then, total HEIGHT, H=u^2/2g=2500/20=125m |
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