CH10 Recitation

Q1: A particle is rotating in a horizontal plane about a fixed axis Q1: A particle is rotating in a horizontal plane about a fixed axis. The radius of its circular path is 10.0 m and it starts to rotate at constant angular acceleration from rest at time t = 0. The angular speed of the particle reaches 36.0 revolutions per minutes at t = 8.00 s. When t = 5.00 s, what is the magnitude of the particle’s radial acceleration

Q2: This figure shows a disk that can rotate about an axis perpendicular to its plane with constant angular velocity ω. By what factor will the rotational kinetic energy of the disk change if the axis of rotation of the disk is shifted from the center to the edge of the disk, keeping ω constant

Q3: The body in this Figure is pivoted at O, and two forces F1 and F2 act on it. If r1 = 1.5 m, r2 = 2.3 m, F1 = 4.5 N, F2 = 5.6 N, 1 = 75o, and 2 = 60o, what is the net torque about the pivot?

Q4: A uniform disk, of mass M = 2 Q4: A uniform disk, of mass M = 2.0 kg and radius R = 20 cm, is mounted on a fixed horizontal axle, as shown below. A block of mass m = 1.0 kg, hangs from a massless cord that is wrapped around the rim of the disk. The block is allowed to fall. Find the magnitude of the tension in the cord. The cord does not slip and there is no friction at the axle.

Q5: A 32. 0 kg wheel, essentially a thin hoop with radius 1 Q5: A 32.0 kg wheel, essentially a thin hoop with radius 1.20 m, is rotating about its axis at 280 rev/min. It must be brought to a stop in 15.0 s. What is the magnitude of the required average power to stop it?

Q6: A mass (M1 = 5.0 kg) is connected by a massless cord to another mass (M2 = 4.0 kg) which slides on a horizontal frictionless surface, as shown in Figure 6. The pulley (radius = 0.20 m) rotates about a frictionless axle. If the acceleration of M2 is 3.5 m/s2, what is the rotational inertia of the pulley?

Q9: Block 1 has mass m1 = 460g, block 2 has mass m2 = 500g and the pulley, which is mounted on a horizontal axle with negligible friction, has radius R = 5.00 cm. When released rest, block 2 falls 75.0 cm in 5.00 s without the cord slipping on the pulley. (a) What is the magnitude of the acceleration of the blocks? What are (b) tension T2 and (c) tension T1? (d) What is the magnitude of the pulley’s angular acceleration? (e) What is its rotational inertia?

Q8: The rigid object shown in figure below consists of three balls and three connecting rods with M=1.6kg, L=0.6m and θ=30o. The balls may be treated as particles, and the connecting rods have negligible mass. If the object has an angular speed of 1.7rad/s, determine the rotational kinetic energy of the object about an axis that passes through point P.

Q7: The figure below gives angular speed versus time for a thin rod that rotates around one end on a horizontal plane. At t = 4.0s, the rod has a rotational kinetic energy of 1.6J. How much average power is required to rotate the rod from t = 4.0s to t = 6.0s?

Q10: Five forces of the same magnitude act on a square merry-go-round that can rotate about point P, at midlength along one of the edges. Rank the forces according to the magnitude of the torque they create about point P, greatest first.