Classical Mechanics Answers

1. A 6.0 kg mass is connected over a pulley to a 3.0 kg mass. What is the resulting acceleration of the masses when they are released? What is the tension in the string when the masses are released?

1. A student is pulling an 11.0 kg sled along flat ground. The student's 30.0 kg sister then sits in the sled. The student then applies a 430 N force at an angle of 35° N of E. If the force of friction is 180 N, what is the acceleration of the sister sitting in the sled.

2. What is the gravitational field strength at a distance of 60.0 km above the surface of the Earth?

3. A 5.5 kg bowling ball hangs by a thin wire in an elevator. Calculate the tension in the wire supporting the bowling ball if the elevator moves: Downward with a constant acceleration of 2.2 m/s2. Upward with a constant acceleration of 1.7 m/s2.

4. A 27.0 kg object is being pulled east across the ground with a horizontal force of 110 N. If the acceleration of the box is 2.82 m/s2, what is the coefficient of kinetic friction?

5. A 6.0 kg mass is placed on a 20° incline which has a coefficient of friction of 0.15. What is the acceleration of the mass down the incline?

1. What centripetal force is required to cause a 12.0 kg object to complete seven revolutions around a horizontal circle of radius 7.50 m in 24.0 s?

2.A satellite is located 2.75 x 10^5 m above the surface of the Earth. What is the period of the satellite’s orbit?

3. The Earth is 1.49 x 10^11 m from the Sun. If the Earth requires 365.25 days to go once around the Sun, what is the centripetal force on the Earth?

4.A 47.0 kg student starts from rest and slides 26.0 m down a hill where the average force of friction is 55.0 N. What is the final speed of the student at the bottom of the hill if the vertical drop was 17.0 m?

5. A 4.0 kg ball is swung at a constant speed in a vertical circle of radius 2.5 m. If the ball completes one revolution in 3.0 s, what is the tension in the rope at the top of the circle?

True or False. Two waves will overlap exactly (i.e., match up) only when the phase of one of the waves is exactly 2pi radians greater or less than than the phase of the other wave

1) A tuning fork of frequency 440 Hz is held above a closed air column that is gradually increased in length. The length of the air column that will produce the second resonance position when the speed of sound is 336 m/s is ___m.

2) The speed of sound where a tuning fork of frequency 262 Hz produces the third resonance position above a closed air column that is 1.59 m in length is ___m/s.

3) The speed of sound is 340 m/s where a tuning fork produces the second resonance position above a closed air column that is 49.8 cm in length. The frequency of the tuning fork is ___ Hz.

True or False. Two waves will overlap exactly (i.e., match up) only when the phase of one of the waves is exactly 2pi radians greater or less than than the phase of the other wave.

1) Match these statements with the correct terms below them. Each statement will only be used once!

incident wave

wave front

medium

wave

wave train

reflected wave

1. A disturbance that moves outwards from its point of origin, transferring energy through the medium
2. An imaginary line that joins all points reached by the wave at the same instant 
3. The material through which the wave travels 
4. A wave front moving from the point of origin toward a barrier
5. A wave front moving away from a barrier 
6. A series of waves forming a continuous series of crests and troughs

2) Sound waves travel through seawater at about 1500m/s. The frequency that would generate a wavelength of 1.55 m in seawater is ___ Hz. 

3) A speaker system generates sound waves at a frequency of 2200 Hz. If the wave speed in air is 325 m/s, the wavelength is ___m

1) The Earth is 1.49 x 10^11 m from the Sun. If the Earth requires 365.25 days to go once around the Sun, what is the centripetal force on the Earth?

2) A satellite is located 2.75 x 10^5 m above the surface of the Earth. What is the period of the satellite’s orbit?

3) A 4.0 kg ball is swung at a constant speed in a vertical circle of radius 2.5 m. If the ball completes one revolution in 3.0 s, what is the tension in the rope at the top of the circle?

1) A pendulum has a mass of 2.35 kg. If the pendulum swings back and forth 110 times in 90.0 seconds, what is the length of the pendulum?

2) A vertical spring is stretched 60.0 cm by a hanging 5.00 kg mass.

a. What is the spring constant?

b. What will be the frequency of vibration of this spring system?

3) Radio telescopes receive waves from distant stars. If such a wave has a wavelength of 24 cm and travels at the speed of light (c = 3.00 x 10 8 m/s), what is the frequency?

4) The speed and wavelength of coastal water waves are 4.0 m/s and 6.0 m respectively. When the waves enter a shallower region, the speed decreases to 1.7 m/s. What is the wavelength in the shallower region?

5) The first resonant length of a closed air column occurs when the length is 40 cm. What will the third resonant length be?

6) A police car with a siren that has a frequency of 900 Hz is moving toward you at 32.0 m/s. Given that the speed of sound is 340 m/s, what is the apparent frequency you hear?

An object is placed 10cm in front of a concave mirror whose radius of curvature is 12cm. calculate 

i. The position of the image 

ii. Magnification