A particle is uncharged and is thrown vertically upward from ground level with a speed of 23.1 m/s. As a result, it attains a maximum height h. The particle is then given a positive charge +q and reaches the same maximum height h when thrown vertically upward with a speed of 29.3 m/s. The electric potential at the height h exceeds the electric potential at ground level. Finally, the particle is given a negative charge -q. Ignoring air resistance, determine the speed with which the negatively charged particle must be thrown vertically upward, so that it attains exactly the maximum height h. In all three situations, be sure to include the effect of gravity.

A charge of -3.45 nC is placed at the origin of an xy-coordinate system, and a charge of 2.30 nC is placed on the y axis at y= 3.90 cm.

Part A: If a third charge, of 5.00 nC , is now placed at the point x = 2.75 cm , y = 3.90 cm find the x and y components of the total force exerted on this charge by the other two charges.

Part B: Find the magnitude of this force

Part C: Find the direction of this force

Two charges, -24

4. [4pt]
Choose the correct statements from the following list referring the possible futures of a Universe that does NOT contain Dark Energy. (Give ALL correct answers, i.e., B, AC, BCD...)

A) At present the visible matter in the Universe is only about 1 percent of the mass needed to reach the critical density.
B) The critical density is equivalent to only six atoms of hydrogen in a volume the size of a typical closet (about one cubic meter).
C) If the density of the Universe is found to be greater than the critical density, the big bang theory must be incorrect.
D) The critical density is the density needed to cause the Big Bang.
E) Probably the ultimate fate of the Universe will be to collapse into a series of large black-holes.
F) If the density of the Universe is less than the critical density the Universe will eventually collapse into a big crunch.
G) It is possible the Universe has undergone a series of big bangs, expansions and contractions.

Newton's Law of Gravitational attraction establishes the relationship among mass, distance fo separation and a constant "G". Describe a valid experiment to determine "G".

• Your original post should be a minimum of 100 words and based on your own unique composition.
• Include examples in your discussion.
• Use MLA guidelines to cite references.
• Show a calculation and explain each step you have done.

LAB: The purpose of this experiment is to study the conditions that must be satisfied for a rigid object to be in static equilibrium. This is done by computing the total torque acting on a meter stick by means of weights suspended at specific locations on the ruler.

If a baseball bat (thicker on one side than the other) is cut at the location where it balances, with both side be of equal weight?

Can the meter stick be balanced if a mass is attached on one side only?

In each of the procedures of this experiment, are the forces also balanced?

How do the different masses being balanced show the properties of a lever?

What are the sources of error in this experiment?

If the meter stick is replaced with a metal stick, and the whole experiment is done inside water (e.g. on the floor of a swimming pool), will the same principles apply as they do in ir? Will it matter if the masses are made of different materials (e.g. if the 200 g is made of iron or lead, or wood)?

Why does a tight rope walker carry a long, horizontal bar to keep him balanced?

Leslie Ballentine develops in QM: A Modern Development an interpretation based on the ensemble interpretation, and responds to most criticisms.

My question: what criticisms still exist against this interpretation such that it is not recognized as the standard interpretation within the physics community?

What problems still exist?

http://en.wikipedia.org/wiki/Ensemble_interpretation

A 1.50-kg block is on a frictionless, 30 degrees inclined plane. The block is attached to a spring (k = 40.0N/m ) that is fixed to a wall at the bottom of the incline. A light string attached to the block runs over a frictionless pulley to a 60.0-g suspended mass. The suspended mass is given an initial downward speed of 1.40m/s. How far does it drop before coming to rest? (Assume the spring is unlimited in how far it can stretch.)

y = _____ m

Please show steps I am confused.

1) explain why we see the moon rise 52 minutes later each evening, and 2) explain why the moon looks different sizes over the course of a month.

A 0.25kg ball moving in a horizontal cirlce at the end of a string has a centripetal acceleration of 4m/s^2. What is the magnitude of the centripetal force exerted by the string on the ball to produce this acceleration?

7. Ball X of mass 1.0 kg and ball Y of mass 0.5kg travel toward each other on a horizontal surface. Both balls travel with a constant speed of 5 m/s until they collide. During the collision, ball Y exerts an average force with a magnitude of 40N for 1/6s on ball X . Which of the following best predicts ball momentum after the collision?

A Ball Y will travel at a speed less than 5 m/s in the same direction of travel as before the collision.

B Ball Y will travel at a speed less than 5 m/s in the opposite direction of travel as before the collision.

C Ball will travel at a speed greater than 5 m/s in the same direction of travel as before the collision.

D Ball Y motion cannot be predicted because the impulse on it is not known.

The answer is C but I do not understand why. Please refrain from using any Calculus

Twins are sliding a rock back and forth on a frozen lake with negligible friction. The mass of each child is 21.0 kg and the mass of the rock is 2.6 kg. Each time the rock is given a push by the child who just caught it, it leaves the hand with a speed of 1.8 m/s relative to the child's hand.

A. The twins are intitially at rest and the sister first slides the rock toward her brother in the positive direction. What is the speed of the sister after she releases the rock?
m/s
B. The brother receives the rock. What is his velocity after he has received it?
m/s
C. The brother then slides the rock to his sister. What is his velocity after he releases the rock?
m/s
D. The sister catches the rock. What is her velocity now?
m/s
E. Can the game go on forever?

a.) no

b.) Cannot be determined    

c.) yes

Explain how to convert solar energy to electricity?.