Chapter 9, Problem 9.3P

Find the center of mass of a sphere of mass M and radius R and a cylinder of mass in, radius r, and height h arranged as shown below. Express your answers in a coordinate system that has the origin at the center of the cylinder.

Two particles of masses m1 and m2 , move uniformly in different circles of radii R1 and R2 R2 about origin in the x, y-plane. The x- and y-coordinates of the center of mass and that of particle 1 are given as follows (where length is in meters and tin seconds): x1(t)=4cos(2t) , y1(t)=4sin(2t) and: xCM(t)=4cos(2t) , yCM(t)=3sin(2t) . a. Find the radius of the circle in which particle 1 moves. b. Find the x- and y-coordinates of particle 2 and the radius of the circle this particle moves.

Find the center of mass of a rod of length L whose mass density changes from one end to the other quadratically. That is, if the rod is laid out along the x-axis with one end at the origin and the other end at x=L , the density is given by (x)=0+(10)(xL)2 , where 0 and 1 are constant values.

Where is the center of mass of a slice of pizza that was cut into eight equal slices? Assume the origin is at the apex of the slice and measure angles with respect to an edge of the slice. The radius of the pizza is R.

Find the center of mass of a cone of uniform density that has a radius R at the base, height h, and mass M. Let the origin be at the center of the base of the cone and have +z going through the cone vertex.

Check Your Understanding Suppose we included the sun in the system. Approximately where would the center of mass of the Earth-moon-sun system be located? (Feel free to actually calculate it.)

Check Your Understanding Notice that the mass of the air in the tank was neglected in the analysis and solution. How would the solution method changed if the air was included? How large difference do you think if would make in the final answer?

Check Your Understanding The changes of momentum for Philae and for Comet 67/P were equal (in magnitude). Were the impulses experienced by Philae and the comet equal? How about the forces? How about the changes of kinetic energies?

Check Your Understanding Would the ball’s change of momentum have been larger, smaller, or the same, if it had collided with the floor and stopped (without bouncing)? Would the ball’s change of momentum have been larger, smaller, or the same, if it had collided with the floor and stopped (without bouncing)?