College
Physics Sample Examination
1. A one meter long organ pipe has one end open and one end closed. If the velocity of sound is 344 m/s, determine the frequency of the 3rd overtone (4th harmonic) for this organ pipe.
(602 hz)
2. A police car
traveling 40 m/s (89.5 mph) catches up and passes a slow moving car traveling
20 m/s (45 mph). The police car is
sounding its siren, which has a frequency of 360 hz. Assume the velocity of sound is 344 m/s
a) What
frequency does the driver of the slow car hear as the police car is catching up
to it?
b) What
frequency does the driver of the slow car hear after the police car has passed
it?
3. Two lawnmowers are running. One has a loudness of 80 db and the other has
a loudness of 78 db. What total loudness
would an observer hear from the two lawnmowers?
4.
In the diagram below there are 3 charges: Q1 = +200 uC;
Q2 = -100 uC; Q3 = - 50 uC.
a) Calculate the Electric Field (magnitude
& direction) at point P. b) If a
charge of + 2 millicoulombs were place at point P,
what would be the resultant force (magnitude and direction) on the charge?
5. Two metal plates, 40 cm by 80 cm as shown in the diagram below, are placed a distance of 4 cm apart and then charged with equal and opposite amounts of charge. When an electron is moved from the positive to the negative plate, it requires work of 3.2 x 10-17 Joules (Use the concept that Work = Force . Distance). For these plates, determine: a) The electric field between the plates. b) The amount of charge on each plate. c) The speed of the electron when it reaches the negative plate if it were released with zero velocity at the positive plate.
a) 5000 n/c; b)1.42 x 10 -9 c; c) 8.39 x 106 m/s
6. Two charged thin
conducting spherical shells are shown in the diagram below, where Q1 = + 200 uC,
Q2 = - 120 uC, R1 = 40 cm, R2 =80 cm. For this charge distribution, determine the Electric Field (magnitude and direction) at the points: a) r = 20 cm. b) r = 60 cm. c) r = 100 cm.
a) E = 0 n/c; b) E = 5 x 106 n/c outward; c) E = 7.2 x 105 n/c outward
7.
An edge on view of four very large (infinite) sheets of charge is shown
below. The magnitude of the electric
fields are E1 = 1000 n/c, E2 = 3000 n/c, E3 = 2000 n/c, and E4 = 1000 n/c.
a) Determine the resultant electric field (magnitude and direction) due to all four infinite sheets of charge at the positions A, B, C, D, E shown in the diagram below
A) + 1000 n/c x; B) + 3000 n/c x; C) - 3000 n/c x; D) +1000 n/c x; E) -1000 n/c x
8. Two infinitely long charged wires are shown
below. Determine the resultant force
(magnitude and direction) on charge Q due to the infinitely long wires.
