The $$x$$ and $$y$$ coordinates of the particle at any time are $$x=5 t-2 t^2$$ and $${y}=10{t}$$ respectively, where $$x$$ and $$y$$ are in meters and $$\mathrm{t}$$ in seconds. The acceleration of the particle at $$\mathrm{t}=2$$ s is:

 1 $$5\hat{i}~\text{m/s}^2$$ 2 $$-4\hat{i}~\text{m/s}^2$$ 3 $$-8\hat{j}~\text{m/s}^2$$ 4 $$0$$
Subtopic: Â Acceleration |
Â 82%
From NCERT
NEET - 2017
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A particle moves so that its position vector is given by $$r=\cos \omega t \hat{x}+\sin \omega t \hat{y}$$ where $$\omega$$ is a constant.  Based on the information given, which of the following is true?

 1 Velocity and acceleration, both are parallel to $$r$$. 2 Velocity is perpendicular to $$r$$ and acceleration is directed towards the origin. 3 Velocity is not perpendicular to $$r$$ and acceleration is directed away from the origin. 4 Velocity and acceleration, both are perpendicular to $$r$$.
Subtopic: Â Acceleration |
Â 70%
From NCERT
NEET - 2016
To view explanation, please take trial in the course.
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