Which is a result of using a machine?
The mechanical advantage makes the work output greater than the work input.
The machine can put out force without having any force applied to it.
Alarge force can be exerted through a long distance to have a small force exerted through a short distance.
Alarge force can be exerted through a short distance to have a small force exerted through a long distance.

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

If anyone who can me with this hw? i would really appreciate it

If a star is moving toward earth, it is