Two people, one of mass 76.4 kg and the other of mass 58.0 kg, sit in a rowboat of mass 84.4 kg. With the boat initially at rest, the two people, who have been sitting at opposite ends of the boat 2.14 m apart, now exchange seats. Friction between the boat and water is negligible. How far will the boat move?

The potassium chloride molecule (KCl) has a dipole moment of 8.90*10^-30 C·m.

(a) Assuming that this dipole moment arises from two charges, each of magnitude 1.6*10^-19 C, separated by distance d, calculate d. Correct: Your answer is correct. 5.56e-11m (

(b) What is the maximum magnitude of the torque that a uniform electric field with magnitude 6.90*10^5 N/C can exert on a KCl molecule? Correct: Your answer is correct. 6.14e-24m

(c) Suppose that the electric field of part (b) points in the +y direction. What are the possible directions of the KCL dipole moment which would result in a torque having the magnitude calculated in part (b), and having a direction of +z? Choose all that apply. -y direction , -x direction, 45 degrees CCW from +x in the xy plane, +y direction, 45 degrees CW from +x in the xy plane, +x direction

(d) Continue to suppose that the electric field of part (b) points in the +y direction. If the dipole swings from an initial orientation pointing in a direction 20.0 degrees CCW away from the -x axis to a final orientation pointing in a direction 20.0 degrees CW away from the -x axis, what is the change in the dipole's electric potential energy? The motion is entirely in the xy plane. _J?

(I got a and b correct just need c and d and how to do them)

A ski starts from rest and slides down a 24 ∘ incline 95 mlong.

Part A

If the coefficient of friction is 0.085, what is the ski's speed at the base of the incline?

Express your answer using two significant figures.

Part B

If the snow is level at the foot of the incline and has the same coefficient of friction, how far will the ski travel along the level? Use energy methods.

Express your answer using two significant figures.

A 4.90 mm -diameter copper ball is charged to +60.0 nC .

What fraction of its electrons have been removed?

A rocket of total mass m_tot = 15000 kg is initially travelling through space at 500 m/s. If it still has 11500 kg of fuel remaining, and the exhaust speed of the rocket is v(exhaust) = 3200 m/s, what is the maximum speed of the rocket?

The magnetic field inside a

5.0-cm-diameter solenoid is 2.0 T and decreasing at 3.90 T/s.

What is the electric field strength inside the solenoid at a point on the axis?
What is the electric field strength inside the solenoid at a point 2.40 cm from the axis?

Give Planck’s quantum hypothesis to describe black body radiation and derive Planck’s radiation formula

1. A “bed of nails” is a huge number of nails arranged in a piece of wood so that they all point up with the sharp points vertically upward. A person can lay down on the “bed of nails” and rest on these thousands of nails without pain or injury. Explain how this can occur.

2. A huge battleship is made of steel which has a density close to iron (almost ten times that of water) yet it can float. Explain why.

3. When a fluid flows through a constriction in a pipe, does the pressure in the fluid increase, decrease of remain constant. Explain your answer fully.

4. A large tank full of water has a nozzle which is open and water shots out of the nozzle vertically. The calculated speed of efflux of water is , which means the water fountain should rise as high as the upper surface of the water as it drains from the tank. In reality, does this actually happen. Justify your answer.

5. What is the difference between pressure and stress, if any? Explain including the units for each.

1. On a day when the atmospheric pressure is, a diver at the bottom of a fresh water lake at a depth of 26m finds a open glass tube (closed a the bottom) containing an unknown liquid (density = 5.6 g/cm3) which is 1.75 m deep. What is the absolute pressure at the bottom of the unknown liquid?

2. A rectangular shaped dam is 460m deep and 1000m wide. It holds fresh water. What is the total force due to water pressure on the dam?

3. A rectangular block of plastic (density = 3.00 x 102 kg/m³) if dimensions l = 25.0 cm, w = 15.0 cm and h = 12.0 cm is placed in water. A) What volume of the block is submerged? B) A metallic (volume 15.0 cm³) block is now placed on top of the plastic block so that the water level is exactly at the top of the plastic block. What is the density of the metallic block?

4. A fluid flows through a horizontal circular pipe that widens, making a 45^o angle with the y axis as shown below. The thin part of the pipe has radius 3 cm and the speed of the fluid is .15 m/s . If the x axis has origin at the point where the pipe widens, what is the speed of the fluid when x= 10 cm?

5. Liquid toxic waste with a density of 1752 kg/m3 is flowing through a section of pipe with a radius of 0.312m at a velocity of 1.64 m/s. a) what is the velocity of the waste after it goes through a constriction and enters a second section of pipe at a radius of 0.222m? b) If the waste is under a pressure of 850,000 Pa in the first section of pipe, what is the pressure in the second section? c) If the second section of pipe flowing horizontally turns to vertical, how high would the fluid have to rise so that the pressure decreases by 50%?

6. Water is flowing in a pipe has a diameter at point A of 8.00 cm tapering to 3.50 cm at point B. Point B is 12.0 cm below point A. The water pressure at point A is 3.20 x 10⁴ Pa and decreases by 50% at point B. Assume steady, ideal flow. What is the speed of water at point A? What is the speed of the water at point B?

7. Calculate the atmospheric pressure in pascals if the height of a mercury column in a barometer is 760 mm. The density of mercury is 13.6 x 10³ kg/m³.

8. What fraction of an iceberg is above water when floating in fresh water? Assume the density of the iceberg is 917 kg/m³.

9. A cylindrical tank of height 0.40 m is open at the top and has a diameter of 0.16m. It is filled with water (assume it to be an ideal fluid, no viscosity) up to a height of 0.16m. Find the time it takes to empty the tank through a hole of radius 5.0 x 10^-3 m in the bottom of the tank.

10. In a hydraulic lever, the cross sectional areas of the pistons are 0.250 m² and 1.00 m². We minimum amount of force that must be applied to the smaller piston to support a car of mass 1200 kg that is resting on the larger piston?

A 0.650 kg projectile is launched from the edge of a cliff with an initial kinetic energy of 1950 J and at its highest point is 131.8 m above the launch point.

(a) What is the horizontal component of its velocity?

(b) What was the vertical component of its velocity just after launch?

(c) At one instant during its flight the vertical component of its velocity is 25.41 m/s. At that time, how far is it above or below the launch point?

In each of the parts of this question, a nucleus undergoes a nuclear decay. Determine the resulting nucleus in each case.

Part A

227/89 Ac undergoes alpha decay. Determine the resulting nucleus.

For example, if the resulting nucleus is 40/20 Ca enter ^40_20Ca.

Part B

211/83 Bi undergoes beta-minus decay. Determine the resulting nucleus.

For example, if the resulting nucleus is 40/20 Ca enter ^40_20Ca.

Part C

22/11 Na undergoes beta-plus decay. Determine the resulting nucleus.

For example, if the resulting nucleus is 40/20 Ca enter ^40_20Ca.

Part D

98/43 Tc undergoes gamma decay. Determine the resulting nucleus.

Enter your answer in the space below. For example, if the resulting nucleus is 40/20 Ca enter ^40_20Ca.

1. A 58 g steel ball is released from rest and falls vertically onto a steel plate. The ball strikes the plate and is in contact with it for 0.5 ms. The ball rebounds elastically, and returns to its original height. The time interval for a round trip is 7 s. In this situation, the average force exerted on the ball during contact with the plate is closest to:

Start with a railroad car on a frictionless track and use the example of a pulse of light with energy ?E traveling from one end of the car to the other to derive ?E = ?mc 2 . You must define all terms carefully and explain each step.

consider a cube of sides l0 traveling parallel to one side. At what speed would the density of the cube double?

I've heard Astronomers talking about backlit CCD sensors, and talking about how much better they are than other types. What are they, why might I want to get one, and what are the pros/cons of this compared to related technologies?

I've heard reference to many telescope and spacecraft that have a device known as a spectrometer, and I'm curious, what is the purpose of these device? What's the working principal behind them and what do we use them for?