Hi please help: a solid disk of radius R= 70 cm rotates about its center at an angular speed of 43 revolutions per minute. The mass of the disk is M= 7.7 kg. The moment of inertia of a solid disk is given by 1/2 MR^2. What is the rotational kinetic energy (in Joules) of the disk? Answer with three significant figures

A thin rod has a length of 0.537 m and rotates in a circle on a frictionless tabletop. The axis is perpendicular to the length of the rod at one of its ends. The rod has an angular velocity of 0.778 rad/s and a moment of inertia of 1.10 x 10³ kg-m². A bug standing on the axis decides to crawl out to the other end of the rod. When the bug (whose mass is 5 x 10-3 kg) gets where it's going, what is the change in the angular velocity of the rod?

Consider a basketball player spinning a ball on the tip of a finger. If a player performs 1.95 J of work to set the ball spinning from rest, at what angular speed ? will the ball rotate? Model a basketball as a thin-walled hollow sphere. For a men's basketball, the ball has a circumference of 0.749 m and a mass of 0.624 kg .

A thin rod has a length of 0.900 m and rotates in a circle on a frictionless tabletop. The axis is perpendicular to the length of the rod at one of its ends. The rod has an angular velocity of 0.607 rad/s and a moment of inertia of 1.06 x 10-3 kg-m². A bug standing on the axis decides to crawl out to the other end of the rod. When the bug (whose mass is 5 x 10-3 kg) gets where it's going, what is the change in the angular velocity of the rod? Number i Units

A horizontal vinyl record of mass 0.0855 kg and radius 0.101 m rotates freely about a vertical axis through its center with an angular speed of 4.18 rad/s and a rotational inertia of 2.64 x 10-4 kg·m2. Putty of mass 0.0253 kg drops vertically onto the record from above and sticks to the edge of the record.What is the angular speed of the record immediately afterwards?

The figure above shows Einstein spinning on a platform. He is initially spinning at a rate of 1rev/s, and holding his hands a distance of R1 = 80.3 cm away from his body. He then pulls his arms in to a distance of R2 = 40cm, changing his rotational speed. In this problem you can model Einstein’s body as a cylinder with a moment of inertia I = 30MR2, where M is his mass (60kg), and R is the distance his hands are from his body. (Notice that the figure shows him holding weights, but we are going to assume they are massless, to make it simpler!)(a) If he draws his arms in very quickly, you can safely ignore any frictional force on the platform. Assuming this is true, how fast is he rotating after he draws his arms in? (b)  In reality, after he draws his arms in friction will start to slow him down. If this small amount of friction is applying a torque of 4 Nm to the platform, how long would it take before Einstein stops moving?

A playground merry-go-round of radius R = 1.80 m has a moment of inertia of 1 = 290 kgm² and is rotating at 14.0 rev/min about a frictionless vertical axis. Facing the axle, a 29.0 kg child hops on to the merry-go-round and manages to sit down on its edge. What is the new angular speed of the merry-go-round? O 1.11 rad/s 0.903 rad/s O 10.6 rad/s O4.53 rad/s practice q# 2 p. 242 chap 7

A solid sphere with a radius of 0.44 and a mass 0.26 is set to rotate about its center. After a time of 12.1 s, its rotational kinetic is 29.3 J. What is its constant angular acceleration? The moment of inertia for a solid sphere is I=2/5MR2

A wheel rotates with the constant angular acceleration of 2.00 rad/s*^2. If the angular speed of the wheel is 4.10 rad/s at t=0, what is the angular displacement of the wheel after 3.10 seconds

A carousel has a radius of 1.70 m and a moment of inertia of 122 kg - m². A girl of mass 43.5 kg is standing at the edge of the carousel, which is rotating with an angular speed of 3.20 rad/s. Now the girl walks toward the center of the carousel and stops at a certain distance from the center d. The angular speed of the carousel is now 5.0 rad/s. How far from the center, in meters, did the girl stop? m