Answer:
Explanation:
Given
radius 
Charge on surface 
Point Charge inside sphere 
Electric Field at 
Treating Surface charge as Point charge and applying Gauss law

where A=surface area up to distance r



Answer:
3.9 m/s
Explanation:
We are given that
Mass of car,m=
Initial velocity,u=0
Distance,s=5.9 m

Average friction force,f=
We have to find the speed of the car at the bottom of the driveway.
Net force,
Where 
Acceleration,


v=3.9 m/s
D.all of the above is the answer for this question
Answer:reflection by dust particles in air