Six dogs pull a two-person sled with a total mass of 220 kg. the coefficient of kinetic friction between the sled and the snow is 0.08. the sled accelerates from rest at 0.75 m/s2 until it reaches a speed of 12 km/h. a) what is the work done by the dogs in the accelerating phase? b) what is the maximum power output by the dogs? c) what is the pulling force from the dogs (assumed to be horizontal)?

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