Two friends on roller-skates are standing `5m` apart facing eachother. One of them throws a ball of `2kg` towards the other, who catches it. How will this activity affect the position of the two? Explain your answer.

10 friends (5 boys P, Q, R, S and T and 5 girls A, E, I, O and U) are playing a game and they are sitting in a circle. The distance between every two friends is equal. Two boys and two girls are facing opposite to the centre of the circle and other 6 friends are facing towards the centre of the circle. A is the fourth to the left of O, who is third to the right of P. R is second to the right of T, who is not near to E. There are three friends between I and R. S is second to the left of U and facing the centre of the circle. P and E are sitting opposite and facing each other. I is second to the left of Q. A is facing opposite to the centre of the circle. More than three boys or girls are not sitting together. Not more than two friends who are facing opposite to the centre of the circle are sitting together. What is the position of I vis- a -vis A ?

10 friends (5 boys P, Q, R, S and T and 5 girls A, E, I, O and U) are playing a game and they are sitting in a circle. The distance between every two friends is equal. Two boys and two girls are facing opposite to the centre of the circle and other 6 friends are facing towards the centre of the circle. A is the fourth to the left of O, who is third to the right of P. R is second to the right of T, who is not near to E. There are three friends between I and R. S is second to the left of U and facing the centre of the circle. P and E are sitting opposite and facing each other. I is second to the left of Q. A is facing opposite to the centre of the circle. More than three boys or girls are not sitting together. Not more than two friends who are facing opposite to the centre of the circle are sitting together. Which two girls are sitting facing opposite to the centre of the circle ?

10 friends (5 boys P, Q, R, S and T and 5 girls A, E, I, O and U) are playing a game and they are sitting in a circle. The distance between every two friends is equal. Two boys and two girls are facing opposite to the centre of the circle and other 6 friends are facing towards the centre of the circle. A is the fourth to the left of O, who is third to the right of P. R is second to the right of T, who is not near to E. There are three friends between I and R. S is second to the left of U and facing the centre of the circle. P and E are sitting opposite and facing each other. I is second to the left of Q. A is facing opposite to the centre of the circle. More than three boys or girls are not sitting together. Not more than two friends who are facing opposite to the centre of the circle are sitting together. Which two boys are facing opposite to the centre of the circle ?

10 friends (5 boys P, Q, R, S and T and 5 girls A, E, I, O and U) are playing a game and they are sitting in a circle. The distance between every two friends is equal. Two boys and two girls are facing opposite to the centre of the circle and other 6 friends are facing towards the centre of the circle. A is the fourth to the left of O, who is third to the right of P. R is second to the right of T, who is not near to E. There are three friends between I and R. S is second to the left of U and facing the centre of the circle. P and E are sitting opposite and facing each other. I is second to the left of Q. A is facing opposite to the centre of the circle. More than three boys or girls are not sitting together. Not more than two friends who are facing opposite to the centre of the circle are sitting together. How many persons are sitting between S and Q ?

10 friends (5 boys P, Q, R, S and T and 5 girls A, E, I, O and U) are playing a game and they are sitting in a circle. The distance between every two friends is equal. Two boys and two girls are facing opposite to the centre of the circle and other 6 friends are facing towards the centre of the circle. A is the fourth to the left of O, who is third to the right of P. R is second to the right of T, who is not near to E. There are three friends between I and R. S is second to the left of U and facing the centre of the circle. P and E are sitting opposite and facing each other. I is second to the left of Q. A is facing opposite to the centre of the circle. More than three boys or girls are not sitting together. Not more than two friends who are facing opposite to the centre of the circle are sitting together. Which of the following boys is not sitting between girls ?

Two skaters P and Q are skating towards each other. Skater P throws a ball towards W every 5 s such that it always leaves her hand with speed 2 ms^(-1) with respect to the ground. Consider two cases: (I) P runs with speed 1 ms^(-1) towards Q while Q remains stationary (II) Q runs with speed 1 ms^(-1) towards P while P remains stationary. Note that irrespective of speed of P, ball always leaves P's hand with speed 2 ms^(-1) with respect to the ground. Ignore gravity. Balls will be received by Q .

Two mirrors, one concave and the other convex, are placed 60 cm apart with their reflecting surfaces facing each other. An object is placed 30 cm from the pole of either of them on their axis. If the focal lengths of both the mirrors are 15 cm, the position of the image formed by reflection, first at the convex and then at the concave mirror, is: