A 1.3 m wide door (mass 2.5 kg) is hinged at one side so that it can rotate without friction about a vertical axis. It is unlatched. A police officer fires a bullet with a mass of 70 g and a speed of 290 m/s into the exact center of the door, in a direction perpendicular to the plane of the door. Find the angular speed of the door just after the collision if the bullet embeds itself in the door. The moment of inertia of a door rotating about its edge is equal to MW² where M is the mass of the door and W is its width. Before After W W

The moment of inertia I of a cheap door of mass M = 4.00 kg (about an axis going through the hinges at the door frame) is I= (1/3) M · R², where R= 0.960 m is the width of the door. The door is initially open and at rest. The door suddenly is struck by a huge and heavy dart of mass m = 0.300 kg traveling perpendicular to the plane of the door at a speed vi = 20.0 m/s. The dart perforates the wooden door getting permanently stuck at the point of impact, which happened to be right next to the free vertical edge of the door (close to the handle). Because the dimensions of the dart are so small (even though they are exaggerated in the picture for clarity) compared to its distance R to the rotational axis (the distance from the hinge to the free vertical edge next to which the dart strikes the door, which is the width of the door R) we can treat the dart as a point mass. I remind you that we learned in class that the moment of inertia of a point mass is I, = m-R², where R is the…

A spherical satellite of approximately uniform density with radius 4.8 m and mass 215 kg is originally moving with velocity (2600, 0, 0) m/s, and is originally rotating with an angular speed 2 rad/s, in the direction shown in the diagram. A small piece of space junk of mass 6.0 kg is initially moving toward the satellite with velocity (-2200, 0, 0) m/s. The space junk hits the edge of the satellite as shown in the figure below, and moves off with a new velocity ( 1300, 480, 0) m/s. Both before and after the collision, the rotation of the space junk is negligible. V3 L Part 1 Ux = Uy = @1 (a) Just after the collision, what are the components of the center-of-mass velocity of the satellite (v, and vy) and its rotational speed w? (For Ux, enter your answer to at least four significant figures.) Part 2 Mi @= i i Save for Later i M, R, 1 V2 m m/s m/s rad/s (b) Calculate the rise in the internal energy of the satellite and space junk combined. J Attempts: 0 of 10 used Submit Answer

A rod of mass M = 3.25 kg and length L can rotate about a hinge at its left end and is initially at rest. A putty ball of mass m = 65 g, moving with speed v = 5.25 m/s, strikes the rod at angle θ = 51° from the normal at a distance D = 2/3 L, where L = 1.3 m, from the point of rotation and sticks to the rod after the collision. 1. What is the angular speed ωf of the system immediately after the collision, in radians per second?

Two 3.40 kg balls are attached to the ends of a thin rod of length 44.0 cm and negligible mass. The rod is free to rotate in a vertical plane without friction about a horizontal axis through its center. With the rod initially horizontal (the figure), a 73.0 g wad of wet putty drops onto one of the balls, hitting it with a speed of 2.97 m/s and then sticking to it. (a) What is the angular speed of the system just after the putty wad hits? (b) What is the ratio of the kinetic energy of the system after the collision to that of the putty wad just before? (c) Through what angle (deg) will the system rotate before it momentarily stops? Putty wad Rotation axis (a) Number i Units (b) Number i Units Units i (c) Number

A diver (m = 60 kg) jumps from a diving board. At takeoff, his angular momentum about the transverse axis is 30 kg⋅m2/s. His radius of gyration about the transverse axis is 0.5 m at this instant. During the dive, he tucks and reduces his radius of gyrations about the transverse axis to 0.2 m.   After he tucks the body, what is his angular velocity about the transverse axis?

A thin rod with a length of 4.0 m and a mass of 4.2 kg is initially at rest. It is capable of spinning around a frictionless axle that goes through the top of the rod. A 2.5 kg mass of clay collides perfectly idealistically with the bottom of the rod. The clay was traveling perfectly horizontally with a speed of 12 m/s before the collision. How fast will the rod with the clay attached to it rotate around the axle in radians per second? The only external force on the clay/rod system come from the axle, which exerts no torque about itself.

Two 3.50 kg balls are attached to the ends of a thin rod of length 36.0 cm and negligible mass. The rod is free to rotate in a vertical plane without friction about a horizontal axis through its center. With the rod initially horizontal (the figure), a 42.0 g wad of wet putty drops onto one of the balls, hitting it with a speed of 3.25 m/s and then sticking to it. (a) What is the angular speed of the system just after the putty wad hits? (b) What is the ratio of the kinetic energy of the system after the collision to that of the putty wad just before? (c) Through what angle (deg) will the system rotate before it momentarily stops? Putty wad Rotation axis

A 45 kg figure skater is spinning on the toes of her skates at 1.3 rev/s. Her arms are outstretched as far as they will go. In this orientation, the skater can be modeled as a cylindrical torso (40 kg, 20 cm average diameter, 160 cm tall) plus two rod-like arms (2.5 kg each, 71 cm long) attached to the outside of the torso. The skater then raises her arms straight above her head. In this latter orientation, she can be modeled as a 45 kg, 20-cm-diameter, 200-cm-tall cylinder. Part A What is her new rotation frequency, in revolutions per second? Express your answer in revolutions per second. ► View Available Hint(s) W₂ Submit Provide Feedback ΑΣΦ ? rev/s

A projectile of mass .050 kg moves to the right with a speed of 4.0 m/s. The projectile strikes and sticks to the end of a rod of mass 0.8 kg, at length 1.2 m from the rod's centre. The rod may rotate freely around a stationary axle pinned through the rod's centre of mass. Find the magnitude of the angular velocity, ω, of the system right after the collision.