Thursday

July 24, 2014

July 24, 2014

Total # Posts: 9

**physical**

An ice cube at 0°C measures 13.9 cm on a side. It sits on top of a copper block with a square cross section 13.9 cm on a side and a length of 19.1 cm. The block is partially immersed in a large pool of water at 88.5°C. How long does it take the ice cube to melt? Assume...

**physical**

An air-cooled motorcycle engine loses a significant amount of heat through thermal radiation according to the Stefan-Boltzmann equation. Assume that the ambient temperature is T0 = 22.3°C (295.45 K). Suppose the engine generates 13.5 hp (10.07 kW) of power and, due to seve...

**physical**

A highway of concrete slabs is to be built in the Libyan desert, where the highest air temperature recorded is 57.8 °C. The temperature is 23.1 °C during construction of the highway. The slabs are measured to be 11.7 m long at this temperature. How wide should the expa...

**physical**

Steel rails for a train track are laid in a region subject to extremes of temperature. The distance from one juncture to the next is 4.41 m, and the cross-sectional area of the rails is 60 cm2. If the rails touch each other without buckling at the maximum temperature, 60.0 &de...

**physical**

Two identical half-open pipes each have a fundamental frequency of 450 Hz. What percentage change in the length of one of the pipes will cause a beat frequency of 13.0 Hz when they are sounded simultaneously? Assume the speed of sound in air is 342 m/s.

**physical**

You are traveling in a car toward a hill at a speed of 42.1 mph. The car's horn emits sound waves of frequency 251 Hz, which move with a speed of 343 m/s. a) Determine the frequency with which the waves strike the hill. b) What is the frequency of the reflected sound waves...

**physical**

You are driving along a highway at 27.7 m/s when you hear a siren. You look in the rear-view mirror and see a police car approaching you from behind with a constant speed. The frequency of the siren that you hear is 1830. Hz. Right after the police car passes you, the frequenc...

**physical**

You are playing a note that has a fundamental frequency of 466.16 Hz on a guitar string of length 59.9 cm. At the same time, your friend plays a fundamental note on an open organ pipe, and 4.0 beats per seconds are heard. The mass per unit length of the string is 1.85 g/m. Ass...

**physical**

Two people are talking at a distance of 2.49 m from where you are, and you measure the sound intensity as 1.47 · 10–7 W/m2. Another student is 4.79 m away from the talkers. What sound intensity does the other student measure?

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