Question

A body moving with a velocity of 15m/s initially along OX has its velocity changed to 15m/s along OF inclined at angle of 60° with OX . determine the change in velocity of body
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Answer 1

Given:

A body moving with a velocity of 15 m/s initially along OX has its velocity changed to 15 m/s along OF inclined at angle of 60° with OX.

To Find:

What is value of  the change in velocity of body?

Solution:

Taking OX as a reference with direction towards right, and also taking OY as a reference with direction upward in plane of paper:

$\mathbf{Initial \ Velocity \ =V_{i}= 15\ \hat{i}}$

$\mathbf{Final \ Velocity \ =V_{f}= 15\cos 60 \ \hat{i}+15\sin 60 \ \hat{j}}$

We know formula of change in velocity:

$\mathbf{Change\ in\ \ Velocity \ =\Delta V=V_{f}-V_{i}=15\cos 60 \ \hat{i}+15\sin 60 \ \hat{j} -15 \ \hat{i}}$

On simplify:

$\mathbf{Change\ in\ \ Velocity \ =\Delta V=-7.5 \ \hat{i}+12.99\ \hat{j} }$

Above is given value of change in velocity.