Chapter 22, Problem 1Q

= Consider the schematic of the molecule shown, with two hydrogen atoms, H, bonded to an oxygen atom, O. The angle between the two bonds is 106°. If the bond length r 0.106 nm long, locate the center of mass of the molecule. The mass mH of the hydrogen atom is 1.008 u, and the mass mo of the oxygen atom is 15.9999 u. (Use a coordinate system centered in the oxygen atom, with the x-axis to the right and the y-axis upward. Give the coordinates of the center of mass in nm.) XCM YOM = = H 53° 53° nm nm r H

An approximate model for a ceiling fan consists of a cylindrical disk with four thin rods extending from the disk's center, as in the figure below. The disk has mass 2.60 kg and radius 0.200 m. Each rod has mass 0.850 kg and is 0.700 m long. HINT (a) Find the ceiling fan's moment of inertia about a vertical axis through the disk's center. (Enter your answer in kg • m².) kg. m² (b) Friction exerts a constant torque of magnitude 0.113 N m on the fan as it rotates. Find the magnitude of the constant torque provided by the fan's motor if the fan starts from rest and takes 15.0 s and 17.5 full revolutions to reach its maximum speed. (Enter your answer in N. m.) N.m

A uniform, thin rod hangs vertically at rest from a frictionless axle attached to its top end. The rod has a mass of 0.780 kg and a length of 1.54 m. (Assume a coordinate system where the +y-direction is up and the +x-direction is to the right. The rod is free to swing about the axle in the x- y plane.) (a) You take a hammer and strike the bottom end of the rod. At the instant the hammer strikes, the force it applies to the rod is (15.71) N. What is the acceleration (in m/s²) of the rod's center of mass at this instant? (Express your answer in vector form.) m/s² a = (b) What is the horizontal force (in N) that the axle exerts on the rod at this same instant? (Express your answer in vector form.) F = N (c) The rod then returns to hanging at rest. You again strike the rod with the hammer, applying the same force, but now you strike it at its midpoint. What now is the acceleration of the center of mass (in m/s²) at the instant of impact? (Express your answer in vector form.) m/s² a = (d)…

Find the net torque on the wheel in the figure below about the axle through O perpendicular to the page, taking a = 9.00 cm and b = 23.0 cm. (Indicate the direction with the sign of your answer. Assume that the positive direction is counterclockwise.) N.m 10.0 N 30.0% 12.0 N 9.00 N

An automobile tire is shown in the figure below. The tire is made of rubber with a uniform density of 1.10 × 103 kg/m³. The tire can be modeled as consisting of two flat sidewalls and a tread region. Each of the sidewalls has an inner radius of 16.5 cm and an outer radius of 30.5 cm as shown, and a uniform thickness of 0.600 cm. The tread region can be approximated as having a uniform thickness of 2.50 cm (that is, its inner radius is 30.5 cm and outer radius is 33.0 cm as shown) and a width of 19.2 cm. What is the moment of inertia (in kg. m²) of the tire about an axis perpendicular to the page through its center? 33.0 cm 16.5 cm Sidewall Ο 30.5 cm Tread i Enter a number. Find the moment of inertia of the sidewall and the moment of inertia of the tread region. Each can be modeled as a cylinder of nonzero thickness. What is the inner and outer radius for each case? What is the formula for the moment of inertia for a thick-walled cylinder? How can you find the mass of a hollow cylinder?…

You have just bought a new bicycle. On your first riding trip, it seems that the bike comes to rest relatively quickly after you stop pedaling and let the bicycle coast on flat ground. You call the bicycle shop from which you purchased the vehicle and describe the problem. The technician says that they will replace the bearings in the wheels or do whatever else is necessary if you can prove that the frictional torque in the axle of the wheels is worse than -0.02 N . m. At first, you are discouraged by the technical sound of what you have been told and by the absence of any tool to measure torque in your garage. But then you remember that you are taking a physics class! You take your bike into the garage, turn it upside down and start spinning the wheel while you think about how to determine the frictional torque. The driveway outside the garage had a small puddle, so you notice that droplets of water are flying off the edge of one point on the tire tangentially, including drops that…

2nd drop down is "up" or "down"

Romeo (79.0 kg) entertains Juliet (57.0 kg) by playing his guitar from the rear of their boat at rest in still water, 2.70 m away from Juliet, who is in the front of the boat. After the serenade, Juliet carefully moves to the rear of the boat (away from shore) to plant a kiss on Romeo's cheek. (a) How far (in m) does the 81.0 kg boat move toward the shore it is facing? m (b) What If? If the lovers both walk toward each other and meet at the center of the boat, how far (in m) and in what direction does the boat now move? magnitude m direction ---Select---

2nd image is the same for all drop downs