Numerical Problems | Chapter 4 | Rotational & Circular Motion | Physics 11th | National Book

Click on the link below for latest videos. https://whatsapp.com/channel/0029VaGr... 4.1 In a workshop a bicycle tyre of radius 33.1cm is rolled across the level floor with an initial velocity of 6.80m/s. Assuming constant angular acceleration, the tyre comes to rest at a distance of 74.8m. Determine (a) initial angular velocity of the tyre; (b) the total number of revolutions it made before coming to rest; (c) the angular acceleration of the tyre; and (d) the time it took before coming to rest. 4.2 The centripetal force on a car of mass 856kg moving along a curve is 7250N. If its speed is 12.0m/s, what is the radius of the curve? 4.3 What is the angular momentum of a 3.6kg uniform cylindrical grinding wheel of radius 31cm when rotating at 1150rpm? (b) How much torque is required to stop it in 7.8s? 4.4 An 80.0kg astronaut stands in the rim of rotating ring shaped space station providing him sufficient artificial gravity 𝒈=𝟗.𝟖〖𝒎𝒔〗^(−𝟐). If the radius of the space station is 1.5km. Calculate his (a) angular velocity, (b) time period and (c) frequency of rotation. 4.1 The front wheel of a tractor travels 700 revolutions while the rear wheel 280 in a time interval of 40 seconds. Find their angular velocities. 4.2 A car, that has centre of gravity 0.4m above the Earth’s surface, passing through a curve whose speed limit is 15m/s. Find radius of the curve. 4.3 Earth rotates about its own axis. What will be its angular momentum when its average angular speed around its axis is 𝟕.𝟐𝟗×〖𝟏𝟎〗^(−𝟓) 𝒓𝒂𝒅/𝒔? 4.4 A space ship, having cylindrical shape, is rotated at a speed of 20rpm about its axis in order to provide artificial gravity to its inhabitants. If the spaceship has a diameter of 8m, find the artificial gravity it provides. Q. Encircle the correct option. If size (length) of the wings of a fan is increased, its rotational speed, for the same voltage and current, will (a) increase (b) decrease (c) may increase or decrease (d) remain constant In a body, angular acceleration is produced by (a) net force (b) power (c) pressure (d) net torque An astronaut feels weightless inside the international space station. It is because the international space station is (a) outside the gravitational field of Earth (b) freely falling (c) at rest (d) in motion What is the value of angular acceleration of the minute hand of your wrist watch? Define the following angular quantities: Displacement, velocity, acceleration. Determine the relation between linear and angular displacement: linear and angular velocity: linear and angular acceleration: Is centripetal force a fundamental force or a force provided by any of the fundamental force? Can any combination of the fundamental forces provide centripetal force? There are generally double tyres in heavy vehicles on one side of an axle. Will its moment of inertia be different from that of a single tyre? Why it is best to have the blades rotate in opposite direction for a helicopter having two sets of lifting blades? If diameter of Earth becomes half and there is no change in its mass, what affect will be there on the rotational speed of Earth around its own axis? Why does in circular motion, a tangential acceleration can change the magnitude of the velocity but not its direction? Why does usually the value of artificial gravity is smaller than 9.8〖ms〗^(-2)? Why is gyroscope used in aeroplanes? How the rotation of a flywheel helps to even out the power delivery from the engine? What will be the angular velocity of fly wheel of an engine if it travels 3000 revolutions in a minute? A car is passing through a turn that is in the form of an arc of a circle of radius 14.5m. What will be the maximum speed limit (the speed at which the car can cross the bridge without losing contact with the road) if the centre of gravity of the car is 0.5m from the ground? A PT teacher rotates his stick at the axis that passes through its centre. If mass of the stick is 200g and its length is 0.8m, find its moment of inertia? A football of mass 450g rotates with an angular speed of 10 revolution/s. If its radius is 11cm, compute its angular momentum? A merry man in a circus is standing with his arms extended on a turn table rotating with angular velocity 10rad/s. He brings his arms closer to his body so that his moment of inertia is reduced to one third of the initial value. Find his new angular velocity. A boy exerts a force of 200N at the edge of the 30.0kg merry-go-round, which has a 2.0m radius. Calculate the angular acceleration produced (a) when no one is on the merry-go-round and (b) when the boy having 20.0kg weight sits 1.5m away from the center. (ignore friction). A wheel shape space station provides an artificial gravity of 5.00m/s^2 to its inhabitants. If it has a diameter of 100m, find its angular speed in rpm.