Classical Mechanics Answers

An earth satellite has a speed of 28070 km/hr when it is at its perigee of 220 km above Earth's surface. Find the apogee distance its speed at apogee, and its period of revolution.

A particle moves under the influence of a central force given by F(r) = - k/ rⁿ. If the particle's orbit is circular and passes through the force center, show that n = 5.

Two blocks are free to slide along the frictionless wooden track shown below. The block of mass m₁ = 4.99 kg is released from the position shown, at height h = 5.00 m above the flat part of the track. Protruding from its front end is the north pole of a strong magnet, which repels the north pole of an identical magnet embedded in the back end of the block of mass m₂ = 10.5 kg, initially at rest. The two blocks never touch. Calculate the maximum height to which m₁ rises after the elastic collision.

Ultrasound bioeffects mainly depend on

[multiple answers]:

A. Wavelength of ultrasound

B. Intensity of irradiation

C. Time of irradiation

D. Velocity of ultrasound

Axial resolution of diagnostic ultrasound can

be improved by [multiple answers]

A. damping

B. pulsing

C. focusing

D. increasing operating frequency

What is the wavelength of a 5MHz

ultrasound pulse in soft tissue?

Assume that the speed of ultrasound

in soft tissue is 1500m/s. [Best

answerl

A. 0.3 mm

B. 0.5 mm

C. 3 mm

D. 5 mm

In which of the following materials

is the speed of ultrasound greatest

[Best answer]

A. Air

B. Bone

C. Water

D. Soft tissue

An ultrasound beam passing through the body

[multiple answers]

A. is attenuated

B. produces heating of tissues

C. can be reflected

D. produces ionization

Which of these statements is (are) true?

1. An object can have zero acceleration and be at rest.

2. An object can have nonzero acceleration and be at rest.

3. An object can have zero acceleration and be in motion.

a) 1 only b) 1 and 3 c) 1 and 2 d) 1, 2, and 3

1. A 3-m-diameter, 7-m-long cylindrical tank is completely filled with water. The tank is pulled by a truck on a level road with the 7-m-long axis being horizontal. Determine the pressure difference between the front and back ends of the tank along a horizontal line when the truck (a) accelerates at 3 m/s² and (b) decelerates at 4 m/s².

2. A 30-cm-diameter, the 90-cm-high vertical cylindrical container is partially filled with 60-cm-high water. Now the cylinder is rotated at a constant angular speed of 180 rpm. Determine how much the liquid level at the center of the cylinder will drop as a result of this rotational motion.

3. A 4-m-diameter vertical cylindrical milk tank rotates at a constant rate of 15 rpm. If the pressure at the center of the bottom surface is 130 kPa, determine the pressure at the edge of the bottom surface of the tank. Take the density of the milk to be 1030 kg/m³.