Answer:
a)
, b) 
Explanation:
a) The maximum possible acceleration that the truck can give to the SUV is:


b) The equation of equilibrium for the truck is:

The force of the SUV's bumper on the truck's bumper is:

Answer: 22.11 ohms
Explanation:
Potential difference(v)=420V
Current(I)=19.0 amp
Resistance(r)=?
r=v/I
r=420/19.0
r=22.11 ohms
Answer:
z = 1.16m
Explanation:
The electric field in a point of the axis of a charged ring, and perpendicular to the plane of the ring is given by:

z: distance to the plane of the ring
r: radius of the ring
Q: charge of the ring
you have that:
E_{z->0} = 0
E_{z->∞} = 0
To find the value of z that maximizes E you use the derivative respect to z, and equals it to zero:
![\frac{dE_z}{dz}=Q[\frac{1}{(z^2+r^2)^{3/2}}+z(-\frac{3}{2})\frac{1}{(z^2+r^2)^{5/2}}(2z)]=0\\\\(z^2+r^2)^{5/2}=3z^2(z^2+r^2)^{3/2}\\\\(z^2+r^2)^2=3z^4\\\\z^4+2z^2r^2+r^4=3z^4\\\\2z^4-2z^2r^2-r^4=0\\\\z^2_{1,2}=\frac{-(-2)+-\sqrt{4-4(2)(-1)}}{2(2)}=\frac{2\pm 3.464}{4}\\\\](https://tex.z-dn.net/?f=%5Cfrac%7BdE_z%7D%7Bdz%7D%3DQ%5B%5Cfrac%7B1%7D%7B%28z%5E2%2Br%5E2%29%5E%7B3%2F2%7D%7D%2Bz%28-%5Cfrac%7B3%7D%7B2%7D%29%5Cfrac%7B1%7D%7B%28z%5E2%2Br%5E2%29%5E%7B5%2F2%7D%7D%282z%29%5D%3D0%5C%5C%5C%5C%28z%5E2%2Br%5E2%29%5E%7B5%2F2%7D%3D3z%5E2%28z%5E2%2Br%5E2%29%5E%7B3%2F2%7D%5C%5C%5C%5C%28z%5E2%2Br%5E2%29%5E2%3D3z%5E4%5C%5C%5C%5Cz%5E4%2B2z%5E2r%5E2%2Br%5E4%3D3z%5E4%5C%5C%5C%5C2z%5E4-2z%5E2r%5E2-r%5E4%3D0%5C%5C%5C%5Cz%5E2_%7B1%2C2%7D%3D%5Cfrac%7B-%28-2%29%2B-%5Csqrt%7B4-4%282%29%28-1%29%7D%7D%7B2%282%29%7D%3D%5Cfrac%7B2%5Cpm%203.464%7D%7B4%7D%5C%5C%5C%5C)
you take the positive value:

hence, the distance in which the magnitude if the electric field is maximum is 1.16m
Thanks answer to the question is b