A positive point charge Q is fixed on a very large horizontal frictionless tabletop. A second positive point charge q is released from rest near the stationary charge and is free to move. Which statement best describes the electric force on q after it is released? O Its force will be greatest just after it is released. O As it moves farther and farther from Q, its force will decrease. O As it moves farther and farther from Q, its speed will increase. O As it moves farther and farther from Q, its electric force will not change. O Its electric force is zero just after it is released.

A solid plastic ball has a radius of 6.0 cm and has a charge of +3.o nC ( in nano-Coulombs) that is uniformly distributed throughout its volume. Imagine there is a proton being held 1.5 cm away from the surface of the solid plastic ball, and then the proton is released. The proton will accelerate away from the ball, as we know, due to the repulsive electric force. Assuming the ball doesn't move, how fast is the proton moving when it is 5.5 cm away from the surface of the ball?

Liquid water has a large dielectric constant of ɛ, = 80. Suppose that a single sodium ion (Na+, carrying a positive charge of +1e) is held in the middle of a beaker of pure water. Compared to the volume of the sodium ion, the volume of the water can be effectively treated as infinite. a) Write down the electric displacement at r distance away from the sodium ion. b) Write down the electric field at r distance away from the sodium ion. c) Write down the electrostatic force that the sodium ion acts on a water molecule that is 2nm away from the ion and oriented with its dipole moment radially away from the ion. d) Calculate the polarization at a distance r = 2nm away from the sodium ion. e) The dipole moment of a water molecule is 6.17 x 10-30C · m. Estimate how much fraction of the water molecules that are at 2nm away from the sodium ion are reoriented by the sodium ion. (Assume that there are only two possible states for these water molecules: either randomly oriented and showing zero…

A helium nucleus, called an alpha particle, has a charge of 2e and mass of 4mp, where e and mp are the charge and mass of a proton, respectiyely. Starting from rest, a proton and an alpha particle are accelerated through a constant electric field E. After a time At, which particle has travelled the furthest distance? O (a) The alpha particle O (b) They travel the same distance O (c) The proton

b) Calculate the net force (magnitude and direction) exerted on charge q by the other four charges, in terms of q, Q, d, and e0. You may draw the force vector to indicate the direction. c) If the charge q is released from rest, and the four other charges held fixed, will the charge q ever “escape” to infinitely far away (assuming an infinite amount of time can pass)? Justify your answer.

Two red blood cells each have a mass of 5.05 × 10-¹4 kg and carry a negative charge spread uniformly over their surfaces. The repulsion arising from the excess charge prevents the cells from clumping together. Once cell carries -2.60 pC of charge and the other -2.70 pC, and each cell can be modeled as a sphere 8.20 µm in diameter. What minimum relative speed u would the red blood cells need when very far away from each other to get close enough to just touch? Ignore viscous drag from the surrounding liquid. V = What is the magnitude of the maximum acceleration amax of each cell? Cmax = m/s m/s²

An electron traveling horizontally enters a region where a uniform electric field is directed upward. What is the direction of the force exerted on the electron once it has entered the field? electron O downward O upward O out of the page, toward the reader O to the left O to the right