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At `t = 1` sec., a particle is at `(1, 2, 0)`. It moves towards `(, -8, 10)` with a constant speed of `50 m//s`. The position of the particle is measured in metres and the times in sec. Assuming constant velocity, the position of the particle at `t = 4s` is :A. `51hat(i) - 98 hat(j) + 100 hat(k)`B. `6 hat(i) - 8 hat(j) + 10 hat(k)`C. `5hat(i) - 10 hat(j) + 10 hat(k)`D. `50 hat(i) - 100 hat(j) + 100 hat(k)` |
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Answer» Correct Answer - A `bar(S) = bar(V) xx t` `bar(V) = |bar(V)| hat(V)` `|bar(V)| = 50 m//s` and `hat(V) = (5 hat(i) - 10 hat(j) + 10 hat(k))/(15)` `bar(S) = 50 ((5hat(i) - 10 hat(j) + 10 hat(k))/(15)) xx 3` `= 50 hat(i) - 100 hat(j) 100 hat(k)` `bar(S) = bar(r )_(f) - bar(r )_(1) = bar(r )_(f) - (hat(i) + 2 hat(j))` `bar(r )_(f) = bar(S) + hat(i) + 2hat(j) = 51hat(i) - 98 hat(j) + 100 hat(k)` |
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