**Problem 1:** A string 1 m long is used to whirl a 100 grams stone in a horizontal circle at a speed of 2 m/s. Find the tension in the string.

**Problem 2:** The moon revolves around the earth in almost a circle of radius 382400 Km in 27.3 days. What is the centripetal acceleration?

**Problem 3:** A ball of mass ‘m’ tied to one end of a string and is whirled from the other end in a vertical circle of radius ‘r’ with constant speed. Find out the tension in the string when the ball is at

(a) the highest point (b) the lowest point

**Problem 4:** A motor car is traveling at a speed of 30 ms^{-1}. If the wheel has a diameter of 1.5 m, find its angular speed in rad/s and rev/ s.

**Problem 5:** An electric motor is running at 1800 rev/min. It comes to rest in 20 s. If the angular acceleration is uniform find the number of revolution made before stopping.

**Problem 6:** What is the moment of inertia of a 100 kg sphere whose radius is 50 cm.

**Problem 7:** What is the K.E of a 5 kg solid ball whose diameter is 15 cm if it rolls across a level surface with a speed of 2 m/s?

**Problem 8:** A cylinder of 50 cm diameter at the top of an incline 29.4 cm high and 10 m long is released and rolls down the incline. Find the linear and angular speed at the bottom. Neglect friction.

**Problem 9:** Show that when a hoop rolls down on an inclined plane, half of K.E is rotational and the other half is translational.

**Problem 10:** A disc without slipping rolls down a hill of vertical height 1000 cm. If the disc starts from rest at the top of the hill, what is its magnitude of velocity at the bottom?