Predict/Explain A carpenter on the roof of a building accidentally drops her hammer. As the hammer falls it passes two windows of equal height, as shown in Figure 232. (a) Is the increase in speed of the hammer as it drops past window 1 greater than, less than, or equal to the increase in speed as it drops past window 2? (b) Choose the best explanation from among the following: I. The greater speed at window 2 results in a greater increase in speed. II. Constant acceleration means the hammer speeds up the same amount for each window. III. The hammer spends more time dropping past window 1.
Modern Physics Lecture 1: Foundations and Special Relativity Position, Time, and Rotation are all continuous symmetries (discrete symmetries such as reflection do not produce the same results as below): Invariance in position (changing where in space you perform your experiment) proves momentum conservation Invariance in rotation (eg. rotating your entire experiment by 90 degrees) proves conservation of angular momentum Invariance in time (changing when in time you perform your experiment, eg. today vs. tomorrow) proves energy conservation Newtonian Mechanics: Inertia F=ma The force of object 1 on object 2 is equal in magnitude to the force of object 2 on object 1 True in an inertial reference frame