中国大学MOOC: A particle of mass m is exerted with a force. Which of the following forces is not a conservative force?(g, k, C, D and γ are constants, and υ is the speed of particle.)
举一反三
- A particle is subjected to forces of [img=18x22]1803a46e41745d3.png[/img], [img=18x22]1803a46e4a7b58d.png[/img], ¼ and [img=20x22]1803a46e54cefd0.png[/img], and the resultant of these forces is [img=78x36]1803a46e5d7bb8f.png[/img]. Which statement is correct? A: The moving direction of the particle must be the same as that of the resultant force [img=14x19]1803a46e65bb7b5.png[/img]. B: The greater the resultant force [img=14x19]1803a46e6dfa97e.png[/img], the greater the speed of the particle. C: The greater the resultant force [img=14x19]1803a46e772e05b.png[/img], the greater the acceleration of the particle. D: The acceleration direction of the particle may or may not be the same as that of the resultant force [img=14x19]1803a46e772e05b.png[/img].
- 1. A charged particle is traveling through a uniform magnetic field. Which of the following statements are true of the magnetic field? A: It exerts a force on the particle parallel to the field. B: It exerts a force on the particle along the direction of its motion. C: It increases the kinetic energy of the particle. D: It exerts a force that is perpendicular to the direction of motion.
- Which of the following explains why a magnetic field does no work on a moving charged particle?( ) A: The magnetic force depends on the speed of the particle. B: There is always an electric field that cancels the work done by the magnetic field. C: The magnetic force is always perpendicular to the direction of motion. D: The magnetic force depends on the direction of motion of the particle. E: The magnetic force is conservative.
- Which forces belong to external forces(). A: spring force B: damper force C: actuator force D: gravity force
- 中国大学MOOC: Which of the following events/accidents is a force majeure event? ( )