Mechanics | Relativity Answers

1.) A 400 kg piano is lifted to the third story with a set of pulleys. The theoretical mechanical advantage is 4.00.

a.) Calculate the effort required to lift the piano.

b.) If the piano is lifted 10.0 m, how far does the effort move?

c.) How much work is done to lift the piano in 10.0 m?

d.) If the piano is lifted 10.0 m in 30.0 seconds, how much power is developed?

A 2.96 kg particle has a velocity of (3.00 i hat - 4.06 j) m/s.

(a) Find its x and y components of momentum.

2. If the coefficient of friction between vehicles and the road is 0.4 and the radius of curvature of

a circular curve of the road is 30 m. What is the maximum speed allowable if there is no

banking?

Find the change in volume of 30 L of a fluid when subjected to a

pressure increase of 2.0 MPa. The bulk modulus of elasticity of the

fluid is 2.24 GPa.

At point A, 3.0 m from a small source of sound that is emitting uniformly in all directions, the sound intensity level is 53 dB. (a) What is the intensity of the sound at A? (b) How far from the source must you go so that the intensity is one-fourth of what it was at A? (c) How far must you go so that the sound intensity level is one-fourth of what it was at A

Sound is detected when a sound wave causes the tympanic membrane (the eardrum) to vibrate. Typically, the diameter of this membrane is about 8.4 mm in humans. (a) How much energy is delivered to the eardrum each second when someone whispers (20 dB) a secret in your ear? (b) To comprehend how sensitive the ear is to very small amounts of energy, calculate how fast a typical 2.0-mg mosquito would have to fly (in mm/s) to have this amount of kinetic energy

In a sinusoidal wave of moderate loudness, the maximum pressure variations are about above and below atmospheric pressure. Find the corresponding maximum displacement if the frequency is 10,000 Hz. In air at normal atmospheric pressure and density, the speed of sound is 344 m/s and the bulk modulus is .

Standing sound waves are produced in a pipe that is 1.20 m long. For the fundamental and first two overtones, determine the locations along the pipe (measured from the left end) of the displacement nodes and the pressure nodes if (a) the pipe is open at both ends and (b) the pipe is closed at the left end and open at the right end

A piano tuner stretches a steel piano wire with a tension of 800 N. The steel wire is 0.400 m long and has a mass of 3.00 g. What is the frequency of its fundamental mode of vibration? What is the number of the highest harmonic that could be heard by a person who is capable of hearing frequencies up to 10,000 Hz?

A sound wave of frequency 300 Hz travels with speed 340ms-1 along

the negative x-direction. Each point of the medium moves up and down through a

total distance of 5.0 mm. Determine the necessary parameters to represent the

wave mathematically.