Answer:
The coefficient of kinetic friction 
Explanation:
From the question we are told that
The length of the lane is 
The speed of the truck is 
Generally from the work-energy theorem we have that

Here N is the normal force acting on the truck which is mathematically represented as
is the change in kinetic energy which is mathematically represented as
=>
=>

=> 
=> 
Answer:
T=7.4 N hence T<30 N
Explanation:
The figure is likely to be similar to the one attached. Writing the equation for forces we have
F-T=Fa/g where F is the force, T is tension, a is acceleration and g is acceleration due to gravity. Substituting the figures we have the first equation as
30 N - T = (30/9.81)a
Also, we know that T=F*a/g and substituting 10N for F we obtain the second equation as
T = (10/9.81)a
Adding the first and second equations we obtain
30 = 4.077471967
a Hence

and T=a hence
T is approximately 7.4 N
Answer:
E = k Q 1 / (x₀-x₂) (x₀-x₁)
Explanation:
The electric field is given by
dE = k dq / r²
In this case as we have a continuous load distribution we can use the concept of linear density
λ= Q / x = dq / dx
dq = λ dx
We substitute in the equation
∫ dE = k ∫ λ dx / x²
We integrate
E = k λ (-1 / x)
We evaluate between the lower limits x = x₀- x₂ and higher x = x₀-x₁
E = k λ (-1 / x₀-x₁ + 1 / x₀-x₂)
E = k λ (x₂ -x₁) / (x₀-x₂) (x₀-x₁)
We replace the density
E = k (Q / (x₂-x₁)) [(x₂-x₁) / (x₀-x₂) (x₀-x₁)]
E = k Q 1 / (x₀-x₂) (x₀-x₁)
Look on this website http://hyperphysics.phy-astr.gsu.edu/hbase/phyopt/sinslit.html