For an object sitting on a surface that has a maximum force of static friction Fs, max and a normal force Fn, which equation can be used to calculate the
coefficient of static friction?

D. μs = Fs/Fn

Explanation:

The static friction coefficient, is always less than 1, for this reason, the friction force will always be less than the force of the body weight.

a small object of mass 3.66 g and charge -17.6 µc is suspended motionless above the ground when immersed in a uniform electric field perpendicular to the ground. what are the magnitude and direction of the electric field?

in simple terms, the principle states that the buoyancy force on an object is equal to the weight of the fluid displaced by the object, or the density of the fluid multiplied by the submerged volume times the gravitational acceleration, g. this is also known as upthrust.