Enable contrast version

# Tutor profile: Christodoulos K.

Inactive
Christodoulos K.
Friendly & competent tutor with expertise in Applied Maths & Physics
Tutor Satisfaction Guarantee

## Questions

### Subject:Physics (Newtonian Mechanics)

TutorMe
Question:

A mass, $$m=14kg$$, is pulled with a force P, on an inclined slope of $$w=25degrees$$ with an acceleration of $$a=2.6m/s^2$$. The coefficient of friction is$$f=0.18$$. Find force P.

Inactive
Christodoulos K.

Draw out a Free Body Diagram to acquire the following equilibrium equations (where N = normal force, F = Friction force): $$F+ma+mgsin(w)=P$$ $$N = mgcos(w)$$ Thus: $$N = 124.47N$$ Using the Coulomb model of friction: $$F = fN=0.18\times124.47N = 22.41N$$ Hence, using the first equilibrium equation, P is found to be: $$P=116.85N$$.

### Subject:Mechanical Engineering

TutorMe
Question:

What is the creep phenomenon exhibited by materials and is this phenomenon common in metals?

Inactive
Christodoulos K.

In Materials Science, the time dependent deformation of a material that is subjected to a constant load is known as creep. Unlike perfectly elastic (or Hookean) behavior that describes an instant deformation upon application of a load, a material that undergoes creep can gradually deform over a long period of time. Creep is common in Viscoelastic materials (most polymers) and is also common in metals at elevated temperatures (e.g. "super-alloy" turbine blades found in jet-engines).

### Subject:Differential Equations

TutorMe
Question:

A 1kg mass, m, with initial displacement, x = 10mm, is connected to a shock absorber with spring stiffness k=24N/mm and damping coefficient c=0.2Ns/mm. Using the Second Ordinary Differential Equation of a free mechanical system as $$\frac{d^2x}{dt^2} + \frac{c}{m} \frac{dx}{dt}+ \frac{k}{m} x=0$$ find the particular solution of the system.

Inactive
Christodoulos K.

By substituting values for k,c and m, we get the following expression: $$\frac{d^2x}{dt^2} + 0.2 \frac{dx}{dt}+ 24 x=0$$, given that x(0) = 0.1m and $$\frac{dx}{dt}=0$$ at t=0. The charachteristic equation is: $$m^2 +\frac{m}{5}+ 24 =0$$ so that m = 0.1+4.90j and m = -0.1-4.90j. The general solution can thus be found as: $$x(t) = exp(-0.1t) (Acos(4.9t)+Bsin(4.9t))$$ Applying the two initial conditions x(0) = 0.1m and $$\frac{dx}{dt}=0$$ we arrive at the particular solution: $$x(t) = exp(-0.1t) (10cos(4.9t)+0.2sin(4.9t))$$.

## Contact tutor

Send a message explaining your
needs and Christodoulos will reply soon.
Contact Christodoulos

Start Lesson

## FAQs

What is a lesson?
A lesson is virtual lesson space on our platform where you and a tutor can communicate. You'll have the option to communicate using video/audio as well as text chat. You can also upload documents, edit papers in real time and use our cutting-edge virtual whiteboard.
How do I begin a lesson?
If the tutor is currently online, you can click the "Start Lesson" button above. If they are offline, you can always send them a message to schedule a lesson.
Who are TutorMe tutors?
Many of our tutors are current college students or recent graduates of top-tier universities like MIT, Harvard and USC. TutorMe has thousands of top-quality tutors available to work with you.
BEST IN CLASS SINCE 2015
TutorMe homepage