Zac

An artificial satellite circling the Earth completes each orbit in 120 minutes. (The radius of the Earth is 6.38 106 m. The mass of the Earth is 5.98 1024 kg.)

(a) Find the altitude of the satellite.

________m

(b) What is the value of g at the location of this satellite?

________m/s^2

A light rod of length script l = 1.00 m rotates about an axis perpendicular to its length and passing through its center as in the figure below. Two particles of masses m1 = 4.70 kg and m2 = 3.00 kg are connected to the ends of the rod.

(a) Neglecting the mass of the rod, what is the system's kinetic energy when its angular speed is 2.40 rad/s?

__________J

(b) Repeat the problem, assuming the mass of the rod is taken to be 1.95 kg.

__________J

An airliner lands with a speed of 50.0 m/s. Each wheel of the plane has a radius of 1.25 m and a moment of inertia of 110 kg · m2. At touchdown, the wheels begin to spin under the action of friction. Each wheel supports a weight of 1.40 × 104 N, and the wheels attain their angular speed in 0.46 s while rolling without slipping. What is the coefficient of kinetic friction between the wheels and the runway? Assume that the speed of the plane is constant.

A student sits on a rotating stool holding two 3.4-kg objects. When his arms are extended horizontally, the objects are 1.0 m from the axis of rotation and he rotates with an angular speed of 0.75 rad/s. The moment of inertia of the student plus stool is 3.0 kg · m2 and is assumed to be constant. The student then pulls in the objects horizontally to 0.47 m from the rotation axis.

(a) Find the new angular speed of the student.

______rad/s

(b) Find the kinetic energy of the student before and after the objects are pulled in.

Before__________J

After___________J

I have four female rats. The past couple weeks, I have been trying to figure out how to make a play pen for them. I used to just put them on the bed, but they figured out how to get down from there. Then I started to put them on the couch, since there was nothing for them to climb down on. They are brave enough just to jump from the couch to the ground, so that doesn't work. I have a play pen for my rabbit, but they can climb that. I tried using boxes, but when they finally get bored of the toys inside, they start chewing on the boxes. I have heard of people putting them in the bath tub, but I don't want to because of the chemicals inside the tub.

Does anyone have suggestions on how to make a rat proof play pen?

I am planning to buy a critter nation either today or tomorrow. But I was wondering how easy it is to collapse it. I go out of town a lot and my rats come with me so I was wondering its folds down or will I have to buy another cage to go out of town also?

I bought about a 4 week old dumbo capped rat from the local pet store that sells them as feeders. Yes I know they do have the chance of getting pregnant at that young of an age if they were with males, which she was. I have her seperated from my other rats to make sure she isnt sick and if she is, it doesnt spread to the ones I already have. She has a pretty big belly. She isnt fat through out, and only her lower abdomen. I went back to the store to look at the rest of the babies, and her stomach is far bigger than the others. Is it possible that she is pregnant?