Your teacher gives you a piece of cardboard with two pinholes on it, saying that they are separated by 205 μm ± 3%. in order to test this, you set up a double slit apparatus with the screen at a distance of 3.00 m away from the cardboard. you use a helium-neon laser (wavelength 638.2 nm) to generate an interference pattern. you measure the distance from the first to the seventh nodal line to be 56.9mm. did your teacher give you accurate value for the separation of the pinholes?

A23 kg log of wood begins from rest, 300 m up a sluice (a water track used to transport logs, think of it as an inclined plane with negligible friction) inclined at 20° to the horizontal. after it reaches the flat waterway at the bottom it collides elastically with a 100 kg block of wood initially at rest near the base of the incline. (a) how long does it take the 23 kg log to travel down the incline? (b) what is the speed of the 23 kg log at the bottom of the incline? (c) what are the velocities of both blocks of wood after the collision? (d) what is the total kinetic energy before the collision? (e) what is the kinetic energy of the 23 kg log after the collision? (f) what is the kinetic energy of the 100 kg block of wood after the collision? (g) what is the total kinetic energy after the collision? (h) compare the total initial and total final kinetic energies. is this consistent with what you would expect for elastic collisions? explain!

All the simple machines make work easier to do by changing the or of a force. a. size; type b. work; type c. size; direction d. type; direction

Which of the following are appropriate acceleration units?