By attaching a diffraction-grating spectroscope to the astronomical telescope, one can measure the spectral lines from a star and determine the star's chemical composition. Assume the grating has 3500 lines/cm. (a) If the wavelengths of the star's light are 478.5 nm, 647.4 nm, and 696.4 nm, what are the angles at which the first-order spectral lines occur? 478.5 nm line ° 647.4 nm line ° 696.4 nm line ° (b) At what angles are these lines found in the second-order spectrum? 478.5 nm line ° 647.4 nm line ° 696.4 nm line °

Aroller coaster car moving at a velocity of 30 meters/second has a momentum of 2.5 x 10^4 kilogram meters/second. what is its mass?

Ok i am attempting to my niece attach a galvanized wire (like a tether for a dog) at the corner of two fences, making a tightwire if you will and we drilled a hole in a softball and she hits it. the ? and problem is that we can not get the wire taunt enough where it doesnt sag after hitting the ball once, and the wire sags and wobbbles. its a 15 ft rubber covered galvanized wire and one can adjust the length of the placing of the wire by having it make the corner of 2 fences become a it can be adjusted, however, with all our human strength and pliers we could not make it taunt as possible. is there anything other that attaching it to a car to do this. sorry abt the length but it would mean the world to my niece if i could solve this came up with the entire idea herself, and she is 14 and paid for the wire and did as much work as i did drilling a hole through a softball wide enough for attaching piece at each end of the wire that clips on to the fence. . any ideas welcome if serious. but awesome if it is a fact. much obliged. bucky bukowski buckman

Astone weighing 1.5 kilograms is resting on a rock at a height of 20 meters above the ground. the stone rolls down 10 meters and comes to rest on a patch of moss. the gravitational potential energy of the stone on the moss is joules.