The force of kinetic friction is given by the equation:

We can calculate the frictional force using the values from the question.

There are four force acting on the block: force from gravity, normal force, force of the spring scale, and force of friction. The normal force will be equal and opposite to the force of gravity, allowing us to cancel the forces in the vertical direction. This leaves us with a net force calculation for the horizontal force: the spring scale force and the force of friction. Note that the frictional force remains negative, as it acts in the opposite direction to the spring scale force.

Now that we know the net force and the mass of the block, we can calculate the acceleration using Newton's second law.

This question forces us to combine two equations.

Using substitution, we can solve for the electric field with the variables given in the question stem.

Ohm's Law states that . We are given the current and resistance, allowing us to solve for the voltage.

We also know that . Now that we have the voltage, we can solve for the power.

Finally, we know that . Using this, we can solve for the energy (or work) that is generated by the circuit.

The equation for finding the force on a charge in a magnetic field is

F = qvBsinθ

Where q is charge in coulombs, v is the velocity of the charge, and B is the strength of the magnetic field in Teslas. Since the charge is moving perpendicular to the magnetic field, sinθ =1. Therefore we solve for force by plugging in the values and multiplying.

The first thing to consider when answering this question is the fact that real images are always inverted and virtual images are always upright. Once you have determined one or the other, two answer choices can be eliminated.

The first equation that is necessary for this question is  .

From this we can determine that  is equal to . Since  is a positive number we know the image is real, and thus inverted.  

The second equation to consider is for magnification:  .

If the absolute value of  is greater than one, the image is magnified, and if the value is less than one, it is minimized.

We would expect the image to be minimized.  

Use the equation:

Focal length is negative for convex mirrors, and image distance is negative for virtual images. We are given these values in the question, allowing us to calculate the object distance.

For this problem, use Snell's law: .

In this equation,  is the index of refraction and  is the angle of refraction to the vertical. Using the values given in the question, we can find the resultant angle of refraction.

Take the arcsin of both sides to find the value of .

The relationship between speed of light and the index of refraction is:

In this formula,  is the speed of light in a vacuum,  is the observed speed of light in the substance, and  is the index of refraction. We are given the speed of light in a vacuum and the index of refraction, allowing us ot solve for the speed of light in the crystal.

Centripetal force is given by the equation:

The length of the string represents the radius of the circle being formed. Use the given string length as the radius, along with the mass of the ball and the velocity, to calculate the centripetal force.

The work done is equal to the gravitational potential energy of the block after it has been lifted.

The gravitational potential energy is calculated using the following formula:

We are given the mass and the change in height, and we know the acceleration due to gravity. Using these values, we can solve for the change in potential energy by multiplication.