You are touring a distant planet on which the magnitude of the gravitational acceleration is 65% of that near the earth's surface. For a little adrenaline, you decide to jump off a precipice 500m above the planet's surface. After 5 seconds of free fall, you ignite the jet pack on your back, changing your acceleration to some new, constant value for the rest of your fall. If you reach the surface 26 seconds after ingiting the jet pack, with what speed do you land?

Force Table: If the center ring were to have considerable mass, what effect would it have on the experiment?

In a mall, a shopper rides up an escalator between floors. At the top of the escalator, the shopper turns right and walks 9.26 m to a store. The magnitude of the shopper's displacement from the bottom of the escalator to the store is 16.0 m. The vertical distance between the floors is 5.40 m. At what angle is the escalator inclined above the horizontal?

Hubble's constand and age of the universe question

please show the working out for both parts

Your 64-cmcm-diameter car tire is rotating at 3.8 rev/s when suddenly you press down hard on the accelerator. After traveling 240 mm, the tire's rotation has increased to 6.5 rev/s.

What was the tire's angular acceleration? Give your answer in rad/s2rad/s2.

Express your answer with the appropriate units.

1. Uncle Iroh’s just made a mass M of tea, but it comes off the kettle too hot at a temperature T_hot. Zuko’s asleep, but will scold his uncle if he sees him drinking, so Iroh wants to cool the tea to T_drink< T_hot as quickly as possible. He has a bunch of ice cubes with side length 2l at temperature T_ice<273 K< T_{drink. (assume tea off of kettle is all liquid.)}

The mass-specific heat of the ice is c_{m ice}; the water and tea both have mass-specific heat c_{m water}. The density of ice is ρ in units of mass per volume, and the mass-specific latent heat of melting of the ice is ∆H_m.

a) Assume the tea and ice cubes are completely isolated from the environment. How

many ice cubes must Iroh put in the tea to get it to T_drink ?

b) Some physicist tells you that ice cools tea at a rate

P ∝ A, (1)

where A is the total exposed surface area of the ice. To speed up the process, you decide to cut the ice cubes each into 8 equally sized smaller cubes (by making three cuts on each large cube). If τ_{no cut} is the time it takes to cool the tea without splitting the cubes, and τ_cut is the time it takes using the split cubes, what is the ratio τ _cut/ τ_{no cut}?

c)Given your answers so far, can Iroh cool the tea using the ice much faster than

the environment could? What should his strategy be to cool the tea as quickly as

possible?

A 200 Ω resistor is in series with a 8.50×10⁻² H inductor and a 0.540 μF capacitor.

part A: Compute the impedance of the circuit at a frequency of f1 = 500 Hz and at a frequency of f2 = 1000 Hz .

Enter your answer as two numbers separated with a comma.

part b: In each case, compute the phase angle of the source voltage with respect to the current.

Enter your answer as two numbers separated with a comma.

part c: State whether the source voltage lags or leads the current at a frequency 500 Hz .

part d: State whether the source voltage lags or leads the current at a frequency 1000 Hz .

Please show all work and assumptions made, and if possible explain your thoughts. Thank you!

1. How many human “radiators” are required to produce the same power as the world average of 20 Terawatts ? Assume 2000 Calorie per day diets! Answer is 210 billion but I dont know how to get it

2. What conclusion(s) can you draw from your answer to the previous problem?   
   hint: how does this value compare to the power radiated by all people on earth assuming that each person eats 2000 Calories per day?

A laser beam strikes one end of a slab of material, as in the figure below. The index of refraction of the slab is 1.64. (Assume θ = 46.0

Conceptual Work and Kinetic Energy

For each of the following statements, determine whether it is true or false.
1.)True/False  The spring force is a non-conservative force.
2.)True/False  The kinetic energy of an object does not depend on the reference frame of the observer.
3.)True/False  Spring B is stiffer than A (kA<kB). A person must do more work on the block connected to spring A if both springs are ideal and the blocks are pulled by the same amount.
4.)True/False  If the Moon revolves around Earth in a perfectly circular orbit, then Earth does do work on the Moon.
5.)True/False  Work cannot be done in the absence of motion.
6.)True/False  The kinetic energy can be negative.
7.)True/False  The work a person must do to raise a box onto a platform depends on how fast it is raised.
8.)True/False  The kinetic energy of an object depends on the direction of the motion involved.

I still got 4 more attempts left so please answer carefully.

8. How do people take advantage of thermal expansion for practical purposes? How can thermal expansion cause problems for people?

10. A sealed jar contains only air at room temperature and atmospheric pressure. To what temperature must the air be heated in order for its pressure to double? Give a number, and include units.

Can you confirm, within measurement errors, that the period is proportional to the square root of the length ` of pendulum, and that it is independent of the mass m of the bob? Explain what frequency and period mean in your own words. Also, think about conservation of mechanical energy during the oscillation: when is the kinetic energy maximal, when is it minimum? How about the potential energy? Explain how “conservation of mechanical energy” is manifest in oscillation of simple pendulum.

1. A vertical spring has a spring constant of 2500 N/m. A ball with a mass of 0.25 kg is on top of the spring. Use energy conservation to answer the following questions. Sketch the situation for each part.

A. If the spring is compressed 8.3 cm how much energy is stored in the spring?

B. When you release the spring, it pushes the ball upward. What is the speed of the ball at the instant it leaves the spring? The spring is at its relaxed length at this point.

C. How far above the spring will the ball rise before it stops going up?

The tires of a car make 78 revolutions as the car reduces its speed uniformly from 91.0km/h to 63.0km/h . The tires have a diameter of 0.88m .
Part A

What was the angular acceleration of the tires?

Express your answer using two significant figures.

Part B

If the car continues to decelerate at this rate, how much more time is required for it to stop?

Express your answer to two significant figures and include the appropriate units.

Part C

How far does the car go? Find the total distance.

Express your answer to three significant figures and include the appropriate units.

1) The 3rd bright fringe of a double slit interference pattern is 30.0 cm above the central bright fringe. If the angle from the horizontal to this 3rd bright fringe is 12.0 degrees, what is the distance (in meters) between the double slits and the viewing screen?

2) A 500 nm laser illuminates a double slit apparatus with a slit separation distance of 7.73 μm. What is the angle (in degrees) from the horizontal to the 4th bright fringe?

3)A 680 nm laser illuminates a double slit apparatus with a slit separation distance of 7.83 μm. On the viewing screen, you measure the distance from the central bright fringe to the 2nd bright fringe to be 88.2 cm. How far away (in meters) is the viewing screen from the double slits?  

4) A 600 nm laser illuminates a double slit apparatus with a slit separation distance of 3.55 μm. The viewing screen is 1.50 meters behind the double slits. What is the distance (in meters) from the central bright fringe to the 3nd dark fringe?

5) A 600 nm laser illuminates a double slit apparatus with a slit separation distance of 3.55 μm. The viewing screen is 1.50 meters behind the double slits. What is the distance (in cm) between the 2nd and 3rd dark fringes?