Physics Conceptual Questions - Mixed

In summary: As for the first question, you are supposed to "feel" the answer, not calculate it! The center of mass of a planet must be near its geometric center, right? So, the atmosphere has a much smaller mass than the Earth, and so it would not shift the center of mass much. Also, the atmospheric density decreases rapidly as we go up. So, the center of mass would be even closer to the center of the Earth.But, more precisely, the center of mass of a planet is defined to be the point around which the planet rotates (if it does rotate). So, if the center of mass of the atmosphere were much closer to the surface
  • #36
OlderDan said:
I probably should not be speaking for cristo, but I don't think he was disagreeing with you. I think he was responding to threewingedfury, but since he did not quote the post to which he was replying, the sequence suggested otherwise.

So to all who read here, PLEASE avoid creating such a jumpled thread by keeping problems in separate threads, and please identify the posts to which you are responding if it is not the one directly above yours.

Yes, olderdan is correct, apologies for the way it appeared!

Ja4Coltrane said:
hey christo, sorry to go back to something old but on that first problem, it seems that choice E is only right if T=mg. this bothers me.

As pointed out above, I answered the wrong question. Tcos theta is the answer.

Now I've worked out how to quote more than one thing, I will do in future!
 
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  • #37
i think it should be T cos [tex]\theta[/tex]
bcoz the body is moving with constant velocity and so acc to the Newton's first law of motion it is moving under the balanced forces
 
<h2>1. What is the difference between speed and velocity?</h2><p>Speed is a measure of how fast an object is moving, while velocity is a measure of both the speed and direction of an object's motion.</p><h2>2. What is the difference between weight and mass?</h2><p>Weight is a measure of the force of gravity acting on an object, while mass is a measure of the amount of matter in an object. Weight can vary depending on the gravitational pull, while mass remains constant.</p><h2>3. What is the difference between potential and kinetic energy?</h2><p>Potential energy is the energy an object has due to its position or state, while kinetic energy is the energy an object has due to its motion. Potential energy can be converted into kinetic energy and vice versa.</p><h2>4. What is Newton's First Law of Motion?</h2><p>Newton's First Law of Motion, also known as the Law of Inertia, states that an object will remain at rest or in motion at a constant velocity unless acted upon by an external force.</p><h2>5. What is the difference between elastic and inelastic collisions?</h2><p>In an elastic collision, both momentum and kinetic energy are conserved, while in an inelastic collision, only momentum is conserved. This means that in an inelastic collision, some of the kinetic energy is lost and converted into other forms of energy, such as heat or sound.</p>

1. What is the difference between speed and velocity?

Speed is a measure of how fast an object is moving, while velocity is a measure of both the speed and direction of an object's motion.

2. What is the difference between weight and mass?

Weight is a measure of the force of gravity acting on an object, while mass is a measure of the amount of matter in an object. Weight can vary depending on the gravitational pull, while mass remains constant.

3. What is the difference between potential and kinetic energy?

Potential energy is the energy an object has due to its position or state, while kinetic energy is the energy an object has due to its motion. Potential energy can be converted into kinetic energy and vice versa.

4. What is Newton's First Law of Motion?

Newton's First Law of Motion, also known as the Law of Inertia, states that an object will remain at rest or in motion at a constant velocity unless acted upon by an external force.

5. What is the difference between elastic and inelastic collisions?

In an elastic collision, both momentum and kinetic energy are conserved, while in an inelastic collision, only momentum is conserved. This means that in an inelastic collision, some of the kinetic energy is lost and converted into other forms of energy, such as heat or sound.

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