Object A moves in a circular motion around object B at a uniform velocity, and what motion does it d

According to the gravitational formula f=g*m1*m2 (r 2);

The gravitational force experienced between the two is equal, and if a(m1) moves around b(m2), the acceleration occurs.

a1=f/m1=g*m2/(r^2)；

If b moves around a, the acceleration a2=f m2=g*m1 (r 2);

But the centripetal force (i.e., gravitational force) is equal in both cases.

Unless the masses are equal, there will be a centripetal or centrifugal movement.

With respect to a, b does a uniform circular motion with velocity v.

However, Newton's third law cannot be used for relative motion, and there is an additional field effect.

Addendum: If it is not acted upon by other forces, then the acting force is only gravitational force. (Gravitational force is when any two particles are attracted to each other by a force in the direction of a concentric line.)

The magnitude of this gravitational force is directly proportional to the product of their masses and inversely proportional to the square of their distance, independent of the chemical nature or physical state of the two objects and the intermediary matter. ）

The reason may be the latter.

First of all, the two forces are different, or where does a directional force acceleration come from?

Secondly, b should be stationary relative to a, b is always perpendicular to a's direction of motion, and the distance is always r.

a. It is also subject to other external forces;

If there is only gravitational force between AB, AB will move in a uniform circle around the center of gravity of their system (binary star system), and if the masses of the two are different, their radius and velocity will be different;

b should do a uniform circular motion relative to a, and one possibility is that a is also subject to external force; There are two possible binary systems in which the masses are equal.

Although I don't know what the centripetal force is, and I haven't learned f=mv 2 r, I think this question only examines the knowledge of the reference object, and he doesn't ask a b what force and how much force it is subjected to move, nor does he say which force b rotates around a, so I don't think this problem should be that complicated.

If A is used as a reference, B is moving in a uniform circular motion around A.

Acted by 5 forces:

Gravity g (straight down).

Disc support force (vertical upwards).

pressure of a (straight down).

Disc friction (pointing towards the center of the circle).

the frictional force of a (pointing in the opposite direction to the center of the circle).

CD is an object moving in a uniform circular motion, the linear velocity does not change, the direction changes at all times, and A is wrong. Kinetic energy.

is a scalar and does not change the d pair. The direction of acceleration is always pointing to the center of the circle, and the direction changes all the time, b is wrong. c Pair.

a. The linear velocity of uniform circular motion does not change, but the direction changes, so A is wrong;

b. According to a=v2

r knows that the magnitude of centripetal acceleration does not change, but the direction always points to the center of the circle and changes at all times, so b is wrong;

c. Uniform circular motion, the time of rotation is constant, so C is correct;

d. The magnitude of the centripetal force remains unchanged, and the direction always points to the center of the circle, which changes at all times, so D is wrong;

Therefore, C

aNo, angular velocity = linear velocity radius.

b No, for the same reason.

c pair, period = 2 * angular velocity.

d is not true, rotational speed = angular velocity (2*, other reasons are the same as a by the way to represent pi.

Think for yourself, suppose there are two discs with different diameters rotating, and the linear velocity is equal == the two discs rotate tangentially, and the angular velocity is equal == two discs share the same shaft and rotate at the same angular velocity. With this model, everything like that is fine.

This should be a frame of reference problem, when B is used as the dot A to do a circular motion, it can be seen as B does not move A to do a circular motion. [As shown in the figure respecting the chain A], when A is the center of the circle, it is regarded as A not moving, and B is moving in a circle around A to do Zhichang. [Such as Liang Mengsun Figure B].

Taking object B as the reference, the body of the spring is like a forest, and the body is in a circular motion with B as the center of the circle.

Take the object year A as the reference, and object B uses A as the center of the circle to make a circular motion.

It can be obtained from the equation a=r 2 and the formula a=v 2 r, b is correct.

A and B move together with the disc in a uniform circular motion, and the centripetal force of A doing circular motion is provided by the static friction force of B to A, so the direction of the friction force of B to A is directed to the center of the circle, then the friction force of A to B deviates from the center of the circle; The centripetal force of B doing circular motion is provided by the frictional force of A to B and the frictional force of the disc to B, the centripetal force experienced by B points to the center of the circle, and the frictional force of A to B deviates from the center of the circle, then the frictional force of the disc to B points to the center of the circle, so B is correct, and A, C, and D are wrong

Therefore, choose B

a. When the object moves in a uniform circular motion, the centripetal force always points to the center of the circle, and the magnitude remains the same, so a is correct;

b. For objects moving in a circular motion at a uniform velocity, the external force provides centripetal force, so B is correct;

c. Because it is a uniform circular motion centripetal force f=mv2

The size of r does not change, so c is correct;

d. The direction of the centripetal force is changing all the time in a uniform circular motion, so D is wrong The wrong choice for this question is D