A) 
Let's start by writing the equation of the forces along the directions parallel and perpendicular to the incline:
Parallel:
(1)
where
m is the mass
g = 9.8 m/s^2 the acceleration of gravity

is the coefficient of friction
R is the normal reaction
a is the acceleration
Perpendicular:
(2)
From (2) we find

And substituting into (1)

Solving for a,

B) 5.94 m/s
We can solve this part by using the suvat equation

where
v is the final velocity
u is the initial velocity
a is the acceleration
s is the displacement
Here we have
v = ?
u = 0 (it starts from rest)

s = 8.70 m
Solving for v,

The acceleration of the box up the ramp is 9.65 m/s².
<h3>
What is the magnitude of acceleration of the box?</h3>
The magnitude of the acceleration of the box is calculated by applying Newton's second law of motion as shown below;
F(net) = ma
where;
- m is the mass of the box
- a is the acceleration of the box
The net force on the box is calculated as follows;
F(net) = F - Ff
F(net) = F - μmgcosθ
where;
- θ is the inclination of the plane
- μ is coefficient of friction
F(net) = 170 - (0.3 x 15 x 9.8 x cos55)
F(net) = 144.7
The acceleration of the box is calculated as;
a = F(net) / m
a = (144.7) / (15)
a = 9.65 m/s²
Thus, the acceleration of the box up the ramp is 9.65 m/s².
Learn more about acceleration here: brainly.com/question/14344386
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Answer: 3.12 * 10^12 F ( 3.12 pF)
Explanation: To calculate this capacitor of two hollow, coaxial, iron cylinders, we have to determine the potental differente between them and afeter that to use C=Q/ΔV
The electric field in th eregion rinner<r<router
By using the Gaussian law
∫E*ds=Q inside/εo
E*2*π*rinner^2*L= Q /εo
E=Q/(2*π*εo*r^2)
[Vab]=\int\limits^a_b {E} \, dr
where a and b are the inner and outer radii.
Then we have:
ΔV= 2*k*(Q/L)* ln (b/a)
replacing the values and using that C=Q/ΔV
we have:
C= L/(2*k*ln(b/a)=0.17/(2*9*10^9*3.023)=3.12 pF
Answer:
and 
Magnitude of accleration is
and the direction is 
Explanation:






Average acceleration in the different axes


The components of the acceleration is
and 
The magnitude of acceleration

Direction

The magnitude of accleration is
and the direction is
.