Question

A body is moving with constant speed, in a circle of radius $10 m$ .The body completes one revolution in 4 s .At the end of 3 rd second, the displacement of body (in mi) from its starting point is :

• A. $15 \pi$
• B. $10 \sqrt{2}$
• C. 30
• D. $5 \pi$

Answer 1

Answer: (B)

$10 \sqrt{2}$

Answer 2

From the given figure above , we get
Speed, v = constant
Radius, R = 10 m
T = Time period = 4s
At the end of 3rd second, particle will be at D (Starts from A)
$\therefore$ displacement S = $\sqrt2R$
$=\sqrt2\times10$
$=10\sqrt2$
So, the correect answer is (B) : $10 \sqrt{2}$