Numerical Problems Chapter 5 Rotational and Circular Motion l First Year Physics KPK Syllabus

1. If the plate microwave oven has a radius of 0.15m and rotates at 6.0rev/min, calculate the total distance traveled by the fly during a 2.0 min cooking period. 2. A circular drum of radius 40cm is initially rotating at 400 rev/min. It is brought to stop after making 50 revolutions. What is the angular acceleration and the stopping time? 3. A string 1m long is used to whirl a 100g stone in a horizontal circle at a speed of 2ms-1. Find the tension in the string. 4. The moon revolves around the earth in almost a circle of radius 382400km in 27.3 days. What is the centripetal acceleration? 5. A modern F1 car can accelerate from 0 to 62 mile/h (100km/h) in 2.50s. What is the angular acceleration of its 170 mm-radius wheels? 6. An electric motor is running at 1800 rev/min. It comes to rest in 20s. If the angular acceleration is uniform find the number of revolutions it made before stopping. 7. What is the moment of inertia of a 100kg sphere whose radius is 50cm? 8. A rope is wrapped several times around a cylinder of radius 0.2m and mass 30kg. What is the angular acceleration of the cylinder if the tension in the rope is 40N and it turns without friction? 9. What is the kinetic energy of a 5.0kg solid ball whose diameter is 15m if it rolls across a level surface with a speed of 2ms-1. 10. A cylinder of 50cm diameter at the top of an incline 29.4cm high and 10m long is released and rolls down the incline. Find its linear and angular speeds at the bottom. Neglect friction. 11. A disc without slipping rolls down a hill of vertical height 1000cm. If the disc starts from rest at the top of the hill, what is its magnitude of velocity at the bottom? 12. A motor car is traveling at a speed of 30ms-1. If its wheel has a diameter of 1.5m, find its angular speed in rad/s and rev/s.