The force resisting the motion of a car is taken as being proportional to the square of the car’s
speed. the magnitude of the force at a speed of 20 m s–1 is 800 n.
what effective power is required from the car’s engine to maintain a steady speed of 40 m s–1?
the available answers are:
a 32 kw b 64 kw c 128 kw d 512 kw

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→∞.