Juanita

(a) Common transparent tape becomes charged when pulled from a dispenser. If one piece is placed above another, the repulsive force can be great enough to support the top piece's weight. Assuming equal point charges (only an approximation), calculate the magnitude of the charge if electrostatic force is great enough to support the weight of a 7.00 mg piece of tape held 1.40 cm above another. (The magnitude of this charge is consistent with what is typical of static electricity.)

C

How far apart must two point charges of 55.0 nC (typical of static electricity) be to have a force of 3.40 N between them?

mm

What length (in m) should an oboe have to produce a fundamental frequency of 305 Hz on a day when the speed of sound is 350 m/s? It is open at both ends.

If two successive resonant frequencies for an open ended organ pipe (open at both ends) are 387 Hz and 430 Hz, and the speed of sound in air is 343 m/s, determine the following.

(a) frequency of the fundamental

Hz

(b) length of the pipe

m

(a)

What is the speed of sound (in m/s) in a medium where a 125 kHz frequency produces a 0.928 cm wavelength?

m/s

(b)

Which substance is this likely to be?

A mass of 327 g is attached to a spring and set into simple harmonic motion with a period of 0.266 s. If the total energy of the oscillating system is 7.14 J, determine the following.

(a) maximum speed of the object

m/s

(b) force constant

N/m

(c) amplitude of the motion

m

A mass is attached to the end of a spring and set into oscillation on a horizontal frictionless surface by releasing it from a stretched position of

x = +0.150 m.

The mass of the block is

m = 0.607 kg,

the force constant of the spring is

k = 61.3 N/m.

Determine the following.

(a) force component that the spring exerts on the block just before the block is released (Indicate the direction with the sign of your answer.)

Incorrect: Your answer is incorrect.

What does Hooke's law tell us about the force exerted by a spring? N

(b) angular frequency ω of the resulting oscillatory motion

rad/s

(c) maximum speed of the oscillating mass

m/s

(d) magnitude of the maximum acceleration of the oscillating mass

m/s2

If you can answer any of these according to where a physician can work that would also be great

Setting

Job Duties

Pay scale

Hours worked

Colleagues

Patients

Pro’s

Con’s

A solid cylinder with a mass of 266 kg and radius 0.060 m is rotating with an angular speed of 84.0 rad/s about an axis passing through its center and perpendicular to its end faces. The rotation of the cylinder is slowed down by a factor of 2 by applying a tangential frictional force to it for 5.30 s. What is the magnitude, in N, of the friction force applied to the cylinder?

A force of 40 N is applied tangentially to the rim of a solid disk of radius 0.20 m. The disk rotates about an axis through its center and perpendicular to its face with a constant angular acceleration of 120 rad/s2. Determine the mass of the disk.

Suppose you exert a force of 217 N tangential to a 0.315 m radius 75.0 kg grindstone (a solid disk). (Give your answers to at least 2 decimal places.)

(a)

What torque (in N · m) is exerted? (Enter the magnitude.)

N · m

(b)

What is the angular acceleration (in rad/s2) assuming negligible opposing friction? (Enter the magnitude.)

rad/s2

(c)

What is the angular acceleration (in rad/s2) if there is an opposing frictional force of 21.6 N exerted 2.00 cm from the axis? (Enter the magnitude.)

rad/s2

What is the final velocity, in m/s, of a hoop that rolls without slipping down a 6.50 m high hill, starting from rest?

m/s

(b)

What would be the final velocity, in m/s, if a disk of the same mass and radius as the hoop rolled down the hill?

m/s

A meter stick has a mass of 0.27 kg and balances at its center. When a small chain is suspended from one end, the balance point moves 30.0 cm toward the end with the chain. Determine the mass of the chain.

A 0.0210 kg bullet moving horizontally at 450 m/s embeds itself into an initially stationary 0.500 kg block.

(a)

What is their velocity (in m/s) just after the collision?

Correct: Your answer is correct.

m/s

(b)

The bullet-embedded block slides 8.0 m on a horizontal surface with a 0.30 kinetic coefficient of friction. Now what is its velocity (in m/s)?

Correct: Your answer is correct.

m/s

(c)

The bullet-embedded block now strikes and sticks to a stationary 2.00 kg block. How far (in m) does this combination travel before stopping?

A battleship that is 6.00 ✕ 107 kg and is originally at rest fires a 1400–kg artillery shell horizontally with a velocity of 675 m/s.

(a)

If the shell is fired straight aft (toward the rear of the ship), there will be negligible friction opposing the ship's recoil. Calculate its recoil velocity in meters per second.

m/s

(b)

Calculate the increase in internal kinetic energy in joules (that is, for the ship and the shell). This energy is less than the energy released by the gun powder — significant heat transfer occurs.

J

A thin block of soft wood with a mass of 0.080 kg rests on a horizontal frictionless surface. A bullet with a mass of 4.67 g is fired with a speed of 613 m/s at a block of wood and passes completely through it. The speed of the block is 23 m/s immediately after the bullet exits the block.

(a)

Determine the speed (in m/s) of the bullet as it exits the block.

m/s

Determine if the final kinetic energy of this system (block and bullet) is equal to, less than, or greater than the initial kinetic energy.

equal to the initial kinetic energy

less than the initial kinetic energy

greater than the initial kinetic energy

Correct: Your answer is correct.

(c)

Verify your answer to part (b) by calculating the initial and final kinetic energies of the system in joules.

KEi

= J

KEf

= J

Whether or not an object (such as a plate, glass, or bone) breaks upon impact depends on the average force exerted on that object by the surface. When a 3.8 kg glass figure hits the floor, it will break if it experiences an average force of 712 N. When it hits a tile floor, the glass comes to a stop in 0.014 s. From what minimum height (in m) must the glass fall to experience sufficient force to break?

m

A particle with a mass of 2.70 kg is acted on by a force Fx acting in the x-direction. If the magnitude of the force varies in time as shown in the figure below, determine the following.

WebAssign Plot

(a)

impulse of the force (in kg · m/s )

kg · m/s

(b)

final velocity of the particle (in m/s) if it is initially at rest

m/s

(c)

Find the final velocity of the particle (in m/s) if it is initially moving along the x-axis with a velocity of

−2.90 m/s.

m/s

Suppose a child drives a bumper car head on into the side rail, which exerts a force of 2400 N on the car for 0.500 s. (Assume the initial velocity is in the positive direction.)

(a)

What impulse (in kg · m/s) is imparted by this force? (Indicate the direction with the sign of your answer.)

Incorrect: Your answer is incorrect.

kg · m/s

(b)

Find the final velocity (in m/s) of the bumper car if its initial velocity was 2.90 m/s and the car plus driver have a mass of 200 kg. You may neglect friction between the car and floor. (Indicate the direction with the sign of your answer.)

m/s

A 7.00 ✕ 105 kg subway train is brought to a stop from a speed of 0.500 m/s in 0.400 m by a large spring bumper at the end of its track. What is the force constant k of the spring (in N/m)?