Civil and Environmental Engineering Answers

Suppose 1.00 g of ethyl alcohol vaporizes isobarically at atmospheric pressure (2.013x10⁵ Pa). Its volume in the liquid state is 3.00 cm³, and its volume in the vapor state is 1700 cm³. Find the work done in the expansion and the change in internal energy of the system. Ignore any mixing of the steam and the surrounding air—imagine that the steam simply pushes the surrounding air out of the way.

A 2.0-mol sample of an ideal gas is kept at 1.0°C during an expansion from 2.0 L to 9.0 L.

a.      How much work is done on the gas during the expansion?

b.      How much energy transfer by heat occurs with the surroundings in this process?

c.      If the gas is returned to the original volume by means of an isobaric process, how much work is done on the gas?

A projectile launcher as shown in the Fig. Q1 is used to launch 0.5 kg ball into the air. The launcher is connected to a 1-kg mass and starts from rest with the spring compressed to a length of 15 cm. The un-stretched length of the spring is 75 cm. When the launcher is released from rest, the 1-kg mass will impact the ball and the ball will project in the air. Determine a suitable spring constant and angle θ for ball to reach a maximum height of 20 m (measure from the current position of ball). The Coefficient of restitution between 1-kg mass and ball is 0.8. (Note: first determine an arbitrary angle and find the spring constant for that)

Two string A and B are given. The length if A is twice that of B. The total mass if A is one-third that of B. If the tension in wire A is one-half that of B and the fundamental frequency of A is 400 Hz, what is the fundamental frequency of string B?

The second harmonic of an open pipe has a frequency double the frequency of the third harmonic of a closed pipe 5 m long. How long is the open pipe?

Standing waves are established in a string. The frequency of the wave is 512 Hz and the distance between two successive nodes is 8 cm. Calculate the velocity of the wave in the string.

A standing wave is set up in string 120 cm long. The string vibrates in four segments under a frequency of 120 Hz. Calculate the wavelength and the fundamental frequency of the string.

Longitudinal waves are set up in an aluminum rod. Calculate the velocity of the wave if the modulus of elasticity of aluminum is 6.9×10^11 dynes per sq. cm. and a density of the aluminum is 2.69 gram per cu. cm.

What is the wavelength in water of a compressional wave whose frequency is 400 per second if the speed of wave in water is 1,450 m/s?