let Coefficients of Friction of Rubber on asphalt (dry) =0.7
F= Coefficients of Friction * normal force = 0.7 * 60 =42 N
so the net force of the rubber is zero, meaning it will travel at a constant speed.
When the rubber is travel at 2m/s, 42N is required to keep moving at constant speed
Answer:
(a) 62.69 nJ/m^3
(b) 1015.22 μJ/m^3
Explanation:
Electric field, E = 119 V/m
Magnetic field, B = 5.050 x 10^-5 T
(a) Energy density of electric field = ![\frac{1}{2}\varepsilon _{0}E^{2}](https://tex.z-dn.net/?f=%5Cfrac%7B1%7D%7B2%7D%5Cvarepsilon%20_%7B0%7DE%5E%7B2%7D)
= 6.269 x 10^-8 J/m^3 = 62.69 nJ/m^3
(b) energy density of magnetic field = ![\frac{B^{2}}{2\mu _{0}}](https://tex.z-dn.net/?f=%5Cfrac%7BB%5E%7B2%7D%7D%7B2%5Cmu%20_%7B0%7D%7D)
![=\frac{\left ( 5.05\times 10^{-5} \right )^{2}}{2\times 4\times 3.14\times 10^{-7}}](https://tex.z-dn.net/?f=%3D%5Cfrac%7B%5Cleft%20%28%205.05%5Ctimes%2010%5E%7B-5%7D%20%5Cright%20%29%5E%7B2%7D%7D%7B2%5Ctimes%204%5Ctimes%203.14%5Ctimes%2010%5E%7B-7%7D%7D)
= 1.01522 x 10^-3 J/m^3 = 1015.22 μJ/m^3