PLEASE ANSWER QUICK!! A student pushes a wagon full of bricks with a constant force across the ground. Which of
the following changes would double the acceleration of the wagon?
A. Removing half of the mass in bricks from the back of the wagon
B. Pulling the wagon over grass instead of concrete
C. Reducing the initial force by half
D. Adding twice as many bricks to the back of the wagon

Consider a uniformly charged ring in the xy plane, centered at the origin. the ring has radius a and positive charge qdistributed evenly along its circumference. a)what is the direction of the electric field at any point on the z axis? . b)what is the magnitude of the electric field along the positive z axis? use k in your answer, where k=14πϵ0. d)the ball will oscillate along the z axis between z=d and z=−d in simple harmonic motion. what will be the angular frequency ω of these oscillations? use the approximation d≪a to simplify your calculation; that is, assume that d2+a2≈a2. express your answer in terms of given charges, dimensions, and constants