1996/97 Test 3 Parts B & C

To aid you with your exam preparation, the following are the Parts B and C questions from the 1996/97 third midterm. (NOTE: The Part A questions of the 1996/97 third midterm are the questions in Self-Graded Quiz #3.)

B1. A small object of weight 1.64 N has an apparent weight on the scale of 1.38 N when completely submerged in water. Calculate the volume of the object. Density of water: 1000 kg/m3

B2. A car is moving at 35.0 m/s and approaches a stationary whistle that is emitting a 220-Hz sound. If the speed of sound in air is 343 m/s, what is the frequency heard by the driver?

B3. An organ pipe of length 0.250 m is open at one end and closed at the other. Calculate the second-lowest resonant frequency. The speed of sound in air is 343 m/s.

B4. An electron is placed in a region of space where there is a uniform electric field which is in the +y direction as shown. The magnitude of the electric field is 51.0 V/m. Determine the magnitude and direction of the force on the electron.

B5. Calculate the diameter of a 2.00-cm length of tungsten filament in a small lightbulb if its resistance is 0.0510 ohms. The resistivity of tungsten is 5.65 × 10-8 ohms·m.

C1. At a distance of 10.0 m from a jackhammer, the sound intensity level is 120 dB. Assume that the sound radiates uniformly in all directions and that no energy is absorbed by the air. 

  1. What is the sound intensity at that distance?
  2. How far away would you need to be for the sound intensity level to be 85.0 dB?

C3. A point charge, Q = +2.50 × 10-12 C, is fixed in space. Point A is 10.0 cm from Q and point B is 1.00 cm from Q.

  1. Calculate the magnitude of the potential difference between points A and B.
  2. If an electron is released from rest at point A, calculate the speed of the electron when it reaches point B.

Solutions: