In the following motion processes, in any equal time, the momentum change of the object is always equal () A. Uniform circular motion B. free falling motion C. horizontal throwing motion D. uniform deceleration linear motion

In the following motion processes, in any equal time, the momentum change of the object is always equal () A. Uniform circular motion B. free falling motion C. horizontal throwing motion D. uniform deceleration linear motion

A. Uniform circular motion is subject to the variable force pointing to the center of the circle, so the impulse of the object changes at all times, so the momentum changes are not equal, so a is wrong; B. free falling motion is only subject to gravity, so the gravity impulse of the object is equal in any equal time, so the momentum changes are equal according to the momentum theorem, so B is correct; C. horizontal throwing motion is only subject to gravity, so the object in any equal time The gravity impulse received is equal, so the momentum change is equal according to the momentum theorem, so C is correct; D, the uniform deceleration linear motion is under the action of constant force, so the impulse received by the object is equal in any equal time, so the momentum change is equal, so D is correct; so BCD

Does the momentum of an object moving in a uniform circular motion change when it is subjected to a centripetal force?

Yes, because the direction has changed. The main consideration of this problem is that momentum is a vector. Apart from the size, there is also the problem of direction, which is basically the same as asking whether the speed will change. If you add the size to the question, there will be no change. If you move for a week, the momentum will not change. Judging whether there is a change depends on the direction and size

If the momentum of an object (with constant mass) changes, the speed of the object must change. Right? Why

No, momentum has both magnitude and direction, and the direction is the same as the direction of velocity. For example, when an object moves in a circular motion at a constant speed, momentum changes all the time, but the magnitude of velocity does not change