Average Speed and Velocity – Page 2 – Rankers Physics
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Average Speed and Velocity

Question 1:

A scooter is going towards east at 10 ms–¹ turns right through an angle of 90°. If the speed of the scooter remains unchanged in taking this turn, the change in the velocity of the scooter is :

20.0 ms–¹ in south–western direction
zero
10.0 ms–¹ in southern direction
14.14 ms–¹ in south–western direction
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Solution:

Change in a vector when it is rotated by an angle θ is

\[ \Delta V = 2V sin \left( \frac{\theta}{2} \right) \]

\[ \Delta V = 2\times 10 sin \left( \frac{90^{0}}{2} \right)= 20/\sqrt{2}= 10\sqrt{2}= 14.4 m/s \]

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Question 2:

Figure shows position versus time graph of two rabbits running opposite to each other between two trees. Which of the following statements are true.

Rabbit A has greater magnitude of average velocity.
Rabbit B has greater magnitude of average velocity.
Both the Rabbits have same displacement.
Both the Rabbits have same constant speed.
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Solution:

Distance is equal for both A and B. B is taking lesser time to complete so its speed is higher.

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