A0.954-kg toy car is powered by three d cells (4.50 v total) connected directly to a small dc motor. the car has an effective energy conversion efficiency of 36.1%, meaning that 36.1% of the electric energy applied to the motor is converted into translational kinetic energy. after 7.88 seconds, the car, which is initially at rest, reaches a speed of 1.27 m/s. what is the average current supplied to the car\'s motor?

Intro: a solid ball of radius rb has a uniform charge density ρ. part a: what is the magnitude of the electric field e(r) at a distance r> rb from the center of the ball? express your answer in terms of ρ, rb, r, and ϵ0. part b: what is the magnitude of the electric field e(r) at a distance r express your answer in terms of ρ, rb, r, and ϵ0. part c: let e(r) represent the electric field due to the charged ball throughout all of space. which of the following statements about the electric field are true? check all that apply. e(0) = 0 e(rb)=0 limr→∞e(r)=0 the maximum electric field occurs when r=0 the maximum electric field occurs when r=rb the maximum electric field occurs as r→∞.