A boy ‘A’ is running on a circular track of radius R. His friend, standing at a point O on the circumference of the track is throwing balls at speed `u = sqrt(gR)`. Balls are being thrown randomly in all possible directions. Find the length of the circumference of the circle on which the boy is completely safe from being hit by a ball.

Arjun and Bhishma are running on a circular track of length 600 m (i.e., circumference of the track). Speed of Arjun is 30 m/s and that of Bhishma is 20 m/s. They start from the same point at the same time in the same direction. When will they meet again for the first time?

Figure shows a smasll sphereical bal of mass m rolling down the loop track. Thebasll is released on the linear portion at a verticla height H from the lowest point. The circular part show has a radius R. a. find the kinetic energy of the ball when it is at a point where the radius makes an angle theta with the horizontal. Find the radial and the tangential accelerations of the cente when the ball is at A. c. find the bnormal force and the frictionasl force acting on the ball if H=60 cm, R=10cm theta=0 and m=70 fg.

Figure shows a smasll sphereical bal of mass m rolling down the loop track. Thebasll is released on the linear portion at a verticla height H from the lowest point. The circular part show has a radius R. a. find the kinetic energy of the ball when it is at a point where the radius makes an angle theta with the horizontal. Find the radial and the tangential accelerations of the cente when the ball is at A. c. find the bnormal force and the frictionasl force acting on the ball if H=60 cm, R=10cm theta=0 and m=70 fg.

An athlete is running on a circular track PQRS of radius 100 m shown below He starts from point P and moves clockwise. (i) Find the distance travelled by him and displacement when he (a) reaches Q (b) moves from Q to S (c ) reaches P again after one revolution (ii) If he completes one revolution in 5 minutes find his (a) average speed (b) average velocity

A kid of mass M stands at the edge of a platform of radius R which can be freely rotated about its axis. The moment of inertia of the platform is I . The system is at rest when a friend throws as ball of mass m and the kid catches it. If the velocity of the ball is v horizontally along the tangent to the edge of the platform when it was caught by the kid find the angular speed of the platform after the event.

A kid of mass M stands at the edge of a platform of radius R which can be freely rotated about its axis. The moment of inerti of the platform is I . The system is at rest when a friend throws as ball of mas mand the kid cathces it. If the velocity of the ball is v horiontally along the tangent to the edge of the platform when it was caught by the kid find the angular speed of the platform after the event.

A kid of mass M stands at the edge of a platform of radius R which can be freely rotated about its axis. The moment of inertia of the platform is I . The system is at rest when a friend throws as ball of mass m and the kid catches it. If the velocity of the ball is v horizontally along the tangent to the edge of the platform when it was caught by the kid find the angular speed of the platform after the event.