MCQs | Chapter 4 | Rotational & Circular Motion | Physics 11th | National Book Foundation

Click on the link below for latest videos. https://whatsapp.com/channel/0029VaGr... Q. Encircle the correct option. Which of the following is incorrect? (a) v ⃗=ω ⃗×r ⃗ (b) α ⃗=v ⃗×r ⃗ (c) a ⃗=α ⃗×r ⃗ (d) α ⃗=(∆ω ⃗)/∆t A car turns around a curve at 30km/h. If it turns at double the speed, the tendency to overturn is (a) doubled (b) quadrupled (c) halved (d) unchanged Moment of inertia of a spinning body, about a certain axis, doesn’t depend on (a) distribution of mass around the axis (b) orientation of the axis (c) mass of the body (d) angular velocity of the body The change in angular momentum of a rod, when a torque of 2.5Nm is acted upon it for 2 seconds, is (a) 1.25Js (b) 2.5Js (c) 5Js (d) Zero 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.