Two identical discs of same radius R are rotating about their axes in opposite directions with the same constant angular speed . The discs are in the same horizontal plane. At time , the points and are facing each other as shown in the figure. The relat

Question

Two identical discs of same radius R are rotating about their axes in opposite directions with the same constant angular speed $ω$ . The discs are in the same horizontal plane. At time $t = 0$ , the points $P$ and $Q$ are facing each other as shown in the figure. The relative speed between the two points $P$ and $Q$ is $v_{r}$ . In one time period (T) of rotation of the discs, $v_{r}$ as a function of time is best represented by [2012]

Smart Achievers · Accepted Answer

(1)

At $t = 0$ and $t = T$ the relative velocity will be zero.

At $t = \frac{T}{4}$ and $t = \frac{3 T}{4}$ , the relative velocity will be maximum in magnitude.

Hence graph (1) correctly depicts $v_{r}$ versus $t$ graph.

Solution

1

2

3

4

Ans.
(1)

At $t = 0, t = \frac{T}{2}$ and $t = T$ the relative velocity will be zero.

At $t = \frac{T}{4}$ and $t = \frac{3 T}{4}$ , the relative velocity will be maximum in magnitude.

Hence graph (1) correctly depicts $v_{r}$ versus $t$ graph.

Want Us to Email you About Special Offers & Updates?

Solution

1

2

3

4

Ans. (1) At t=0, t=T2 and t=T the relative velocity will be zero. At t=T4 and t=3T4, the relative velocity will be maximum in magnitude. Hence graph (1) correctly depicts vr versus t graph.

Want Us to Email you About Special Offers & Updates?

Ans.
(1)

At $t = 0, t = \frac{T}{2}$ and $t = T$ the relative velocity will be zero.

At $t = \frac{T}{4}$ and $t = \frac{3 T}{4}$ , the relative velocity will be maximum in magnitude.

Hence graph (1) correctly depicts $v_{r}$ versus $t$ graph.