A 1750-kg car travels at 23 m/s when it crashes into the rear end of a 1500-kg car traveling at 20 m/s in the same direction on nearly frictionless ice. The two cars become stuck together and slide on the ice. How fast do the two cars move together immediately after the collision? *use units*
2.A book weighs 6 newtons.A librarian picks up the book from one shelf and puts it on a shelf 2 metres higher.(a) Calculate the work done on the book. [Show your working].(b) The next person to take the book from the shelf accidentally drops it.The book accelerates at 9.8m/s.Use this information to calculate the mass of the book. [Show your working].
We all know the trick of pretending to lose a cell phone connection, but the receiving person (in reality) can usually tell you have a good connection. This time, you are in luck- you are using a cell phone at 850 MHz, on one side of you is the cell phone tower, and on the other side, a tall building.1) what is the wavelength of your cell phone transmission?2) How far from the building should you stand to lose reception?3) Since the phone companies employ good engineers, that trick won't actually work. However, you happen to see a chain-link fence nearby, and (out of desperation) try to use that as a diffraction grating to scatter the radiation. Estimating the link spacing as 5 cm, will this work?