In an experiment conducted using the young's double-slit apparatus, the separation between the slits is 20 µm. a first-order constructive interference fringe appears at an angle of 2.5o from the zeroth order (central) fringe.
a. what wavelength of light is used in the experiment?
b. at what angle would the fourth-order (m = 4) bright fringe appear?
c. at what angle would the fourth-order (m=4) dark fringe appear?

11. you want to calculate the displacement of an object thrown over a bridge. using -10 m/s2 for acceleration due to gravity, what would be the total displacement of the object if it took 8 seconds before hitting the water?

Mutt and jeff are running along a path each pushing a cart loaded with rocks. if mutt's wagon has a mass two times greater than jeff's and they want to stay together, arriving at their destination at the same time, what must happen? a) jeff should slow down so mutt can catch up. b) mutt must use half as much force to push his cart. c) mutt must use twice as much force to push his cart. d) mutt and jeff will use the same force, but mutt will take bigger steps.

Students design a model roller-coaster track. they place a rubber ball at the highest point on the track and let it go. the ball rolls along the track pulled only by the force of gravity. eventually, it comes to a stop. which change to the design will result in the ball moving the greatest distance?