# Physics Exam 1P 2012 Notes - part 1

HideShow resource information

Notes on questions I got wrong:

• the speed of the waves in the electromagnetic spectrum are the same.

Rabbits  Mate In Very  Unusual eXpensive Gardens

• The name of the process when a light ray passing through a semicircular block of glass hits the surface and is reflected back is called TOTAL INTERNAL REFLECTION.

Above is the path of a light ray entering a right-angled glass block, hitting the inside and being reflected back.

•  Factors that effect car stopping distance if someone is about to be hit:

- Thinking distance which depends on the reaction time of the driver includ. drunk, drugs, tired, distracted, speed of car e.g if the driver was drunk, their reaction time would increase therefore stopping distance would increase, also distance = velocity x time

- Conditon of road surface: muddy, icy, wet i.e. less friction if the road is wet.

- Speed/ velocity/behaviour of person

- Distance of person from car

- Visibilty factor: fog, dirty windscreen

• Coin experiment - before coins were piled on top of eachother on table, now they are spread out on the table. (1) How does this effect total force? (2) How does it effect the pressure caused?

(1) The total force is the same as the number of coins is the same.

(2) The pressure is less  because the same weight is spread over a larger surface area.

• Unit for moment:

-  Correct: Nm or N.m    - Incorrect:  nm or NM

• Two levers: lever A's distance from the pivot is 0.04m and 7N is applied to give a moment of 0.28Nm but lever B's distance from pivot is only 0.02m - Explain why the minimum force needed for it to turn is more tham 7N?

- The distance from the pivot of lever B's is (0.02m) is smaller