Question

A ball is thrown onto a floor at an angle. If its
velocity vector is 4i-3j) (m/s) and restitution
coefficient is2/3
then, the velocity by which it
rebounds is
​

Answer 1

hii

Answer:

et\hat{n}=\alpha\hat{i}+\beta\hat{j}}, (\alpha^2+\beta^2 = 1)

be the normal unit vector. Then

\vec{v}-\vec{u} = \left((\vec{v}-\vec{u})\cdot\hat{n} \right )\hat{n}

This equation along with\alpha^2+\beta^2 = 1, gives

\alpha=-\frac{3}{5}, \beta = \frac{4}{5}.

So, we get

\hat{n}=-\frac{3}{5}\hat{i}+\frac{4}{5}\hat{j}}

Now,

coefficient of rebound,

e=-\frac{\vec{v}\cdot\hat{n}}{\vec{u}\cdot\hat{n}}=-\frac{-3+12}{-12-4}=\frac{9}{16}

Answer 2

Answer:

option A

Explanation:

hope it helps

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