Name___________________________________________________________________
Physics 1402 Practice Problems Exam I
1. A 0.40 kg mass is attached to a spring with a spring constant 160 N/m so that the
mass is allowed to move on a horizontal friction-less surface. The mass is
released from rest when the spring is compressed 0.15 m. Find
(a) the force on the mass
(b) the acceleration at this instant.
2.
If the frequency of an oscillation of the wave emitted by an FM radio station is
88 MHz (M = 1,000,000), determine the wave’s (radio waves travel at the speed
of light, c= 3 X 108 m/s)
(a) period
(b) wavelength
3. The area of a typical eardrum is about 5.0 X 10-5 m2. Calculate the sound power
(energy per second) incident on an eardrum at the threshold of
(a) pain, (I = 1 W/m2)
(b) threshold of hearing, (I = 10-12 W/m2)
4. A train moving at the speed of 40 m/s sounds its whistle, which has a frequency
of 500 Hz. (Speed of sound is 345 m/s)
(a) Determine the frequency heard by a stationary observer as the train
approaches the observer
(b) as the train recedes from the observer
5. Determine the intensity level of sound with an intensity of 5 X 10-7 W/m2.
6. A 2.2 X 10-9 C charge is on the X-axis at x = -1.5 m, a 5.4 X 10-9 C charge is at x
= 2.0 m, and 3.5 X 10-9 C charge is at the origin. Find the net force on the 3.5 X
10-9 C charge.
7. A 2.7 X 10-6 C point charge is on x-axis at X = -3.0 m, and a + 2.0 X 10-6 C point
charge is at x = 1.0 m. Determine the net electric field (magnitude and direction)
on the y-axis at y = + 2.0 m.
8. An FM radio station broadcasts on a frequency of 100.5 MHz. What is the
wavelength of this station? (The speed of light is 3 X 10 m/s, MHz = 1,000,000
Hz)
9. The electric field at a distance of 15 m from a point charge is found to be 85 N/C.
What is the magnitude of the charge?
10. The period of a simple pendulum is determined to be 2.3 s on earth. What would
it be on the moon where g = 1.6 m/s2.
11. What is the intensity of sound with a measured intensity level 64 dB?
(I0 = 10-12 W/m2)