摘要:

Make a top with a white cardboard circle and a pencil. Draw a black circle on the disk. Can you guess what you will see when the top is spun?

ISSN:0031-921X    

DOI:10.1119/1.1527623

出版商:American Association of Physics Teachers    

年代:1998

数据来源: AIP

摘要:

The November editorial worried Newton’s second law and proposed methods of defining mass and of setting up a force scale. Experiment (not definition) shows that forces can be represented by vectors. Experiments also show that inertial mass and gravitational mass are equal, and in Einstein’s view, identical.

ISSN:0031-921X    

DOI:10.1119/1.880130

出版商:American Association of Physics Teachers    

年代:1998

数据来源: AIP

摘要:

Newton’s third law force pairs are sometimes difficult for students to identify, especially when one of the forces produces no discernable acceleration. In the context of a Fermi problem, the third law pairs involved in walking is investigated, paying specific attention to whether the force on the Earth by the walker can impact the Earth’s rotational motion.

ISSN:0031-921X    

DOI:10.1119/1.880131

出版商:American Association of Physics Teachers    

年代:1998

数据来源: AIP

摘要:

Here is a quick and inexpensive way to demonstrate to your class that air is a poor conductor of heat, using an aluminum beaker and a soda can over a Bunsen burner.

ISSN:0031-921X    

DOI:10.1119/1.880132

出版商:American Association of Physics Teachers    

年代:1998

数据来源: AIP

摘要:

We briefly review the classical mechanics of a point particle in a circular billiard system, classifying the possible trajectories. We then show how this system can be approximately realized experimentally, utilizing an analogy with geometrical ray optics, using a laser and cylindrical reflecting surface.

ISSN:0031-921X    

DOI:10.1119/1.880133

出版商:American Association of Physics Teachers    

年代:1998

数据来源: AIP

摘要:

The magnetic properties of common materials such as wood, plastic, glass, and aluminum are demonstrated using small, inexpensive, surplus quadrupole magnets. Paramagnetic rods line up with the field above the magnet while diamagnetic samples line up perpendicular to the field.

ISSN:0031-921X    

DOI:10.1119/1.880134

出版商:American Association of Physics Teachers    

年代:1998

数据来源: AIP

摘要:

A way to demonstrate normal forces using a precision laboratory electronic balance has been reported in this magazine. I propose a simpler and less expensive way of demonstrating normal forces.

ISSN:0031-921X    

DOI:10.1119/1.880135

出版商:American Association of Physics Teachers    

年代:1998

数据来源: AIP

摘要:

A concrete demonstration of Archimedes’ principle of buoyancy without direct reference to density is described. Floating and sinking are explained in terms of the weight andshapeof objects. This can be effective with students who have not mastered ratios.

ISSN:0031-921X    

DOI:10.1119/1.880136

出版商:American Association of Physics Teachers    

年代:1998

数据来源: AIP