Global Warming. Is it real, is it a threat, and who's to blame?

There are three issues here.

Is the Earth warming abnormally now, or is this current trend normal?

If the Earth is warming abnormally, is this a problem?

If the Earth is warming abnormally, can we attribute this to an overactive Sun, or to human activities.

This is a politically-charged issue. There is plenty of data, but the data can be interpreted in more than one way. The NASA Global Climate Web site (Links to an external site.)Links to an external site. provides factual data and different interpretations of the data. The differing interpretations are the problem. We can react. Should we?

What do you think? Do you see any compelling evidence one way or the other? Please support your position with logical statements, concrete examples, and citations of applicable. Please try to avoid political diatribes.

A billiard ball A moving at a speed of 2.4 m / s bumps into a billiard ball B of the same mass, which
are at rest. After the impact, A moves at a speed of 1.4 m / s in a direction that forms the angle 50 ◦
with A's original direction of movement. Determine the magnitude and direction of B's ​​velocity vector by
the impact. (Answer 1.8 m / s; 36 ◦)

You are using a rope to pull a 15 kg suitcase along a level path. There is friction between the suitcase and the floor, so you must pull with some difficulty to get the suitcase moving, needing a force of about 120N. Afterward, you find that by maintaining that force, the suitcase acceleration while sliding along the floor, the coefficient of static friction is 0.81and the coefficient of kinetic friction is 0.40.

a. Draw a force diagram and label all the forces on the suitcase for the static situation.

b. Draw a force diagram and label all the forces on the suitcase for the kinetic situation.

c. Explain the differences between your two force diagrams in part A and part B.

d. Find the acceleration that the suitcase experiences while you're dragging it across the floor.

e. How would your answer to part D change if you decided to add 5kg worth of items to the suitcase?

In a TV picture tube the accelerating voltage is 17.0 kV, and the electron beam passes through an aperture 0.40 mm in diameter to a screen 0.230 m away. What is the uncertainty in position of the point where the electrons strike the screen?

A 6.0-ft-tall girl stands on level ground. The sun is 23 ∘ above the horizon.

How long is her shadow?

Express your answer using two significant figures.

b) A 5.0-m-wide swimming pool is filled to the top. The bottom of the pool becomes completely shaded in the afternoon when the sun is 25 ∘above the horizon.

How deep is the pool?

Express your answer using two significant figures.

A 2.0-m-tall basketball player is standing on the floor a distance d from the basket, as shown in the figure below. He shoots the ball at an angle of 40.0o above the horizontal with a speed of 10.67 m/s and makes the shot. The height of the basket is 3.05 m. What is d

please make sure its detailed.

if density

What is a joule? What is the equivalent unit in the English system?

Describe magnetic inductance and give examples.

Describe R-L, L-C, and L-R-C series circuits, and give examples.

PLEASE DO NOT WTITE IT BY HAND

.

A charged paint is spread in a very thin uniform layer over the surface of a plastic sphere of diameter 20.0 cmcm , giving it a charge of -19.0 μCμC .

Part A: Find the electric field just inside the paint layer.

Part B: Find the electric field just outside the paint layer.

Part C: Find the electric field 7.00 cm outside the surface of the paint layer.

Three 90.790.7 g masses are connected in a triangular shape by massless rigid wires as shown in the first image (which is not drawn to scale). The coordinates of each mass are given in centimeters. Mass A is located at (0,0)(0,0), mass B is at (10.2,19.5)(10.2,19.5), and mass C is at (17.3,13.4)(17.3,13.4). Find the xx- and yy‑coordinates of the center of mass of the triangular object.

Two more 90.790.7 g masses are connected by a straight piece of wire and affixed to the original configuration as shown. The coordinates of mass D are (0,−39.1)(0,−39.1) and the coordinates of mass E are (0,39.1)(0,39.1). Find the xx- and yy‑coordinates of the new center of mass of the combined object.

A 8.6-kg cube of copper (c_Cu = 386 J/kg-K) has a temperature of 750 K. It is dropped into a bucket containing 5.1 kg of water (c_water = 4186 J/kg-K) with an initial temperature of 293 K.

1)

What is the final temperature of the water-and-cube system?

K

2)

If the temperature of the copper was instead 1350 K, it would cause the water to boil. How much liquid water (latent heat of vaporization = 2.26 × 10⁶ J/kg) will be left after the water stops boiling?

kg

3)

Let's try this again, but this time add just the minimum amount of water needed to lower the temperature of the copper to 373 K. In other words, we start with the cube of copper at 750 K and we only add enough water at 293 K so that it completely evaporates by the time the copper reaches 373 K. Assume the resulting water vapor remaining at 373 K. How much water do we need ?

kg

While taking photographs in Death Valley on a day when the temperature is 50.0°C, Bill Hiker finds that a certain voltage applied to a iron wire produces a current of 1.000 A. Bill then travels to Antarctica and applies the same voltage to the same wire. What current does he register there if the temperature is -88.0°C? Assume that no change occurs in the wire's shape and size.

- In your own words, explain potential energy, kinetic energy, conservation of energy and examples in daily life.

- In your own words, explain the definition of work in Physics.

- In your own words, explain Hooke's Law and elastic potential energy.