Final Revision Powerpoint

Question 1

What is the moment of a force relative to the cross product of components?

Answer 1

M = r x F

Question 2

What is Newton’s 2nd Law?

Answer 2

F = ma

Question 3

What are the conditions of equilibrium?

Answer 3

The resultant forces and moments have to equal 0

Question 4

How do we draw a simple support in a free body force diagram?

Answer 4

A force perpendicular to the surface of contact

Question 5

How do we draw a pinjoint in a free body force diagram?

Answer 5

Either with two perpendicular forces or a force at an angle

Question 6

How do we draw a rigid support in a free body force diagram?

Answer 6

Two perpendicular forces and a moment

Question 7

What are the simplifying assumptions for a plane truss?

Answer 7

• Members are pin jointed at their ends
• Forces are only applied at joints
• Each member is acted upon by only two forces

Question 8

What are the two methods to solve a truss?

Answer 8

• Method of Joints:
  We isolate one joint where no more than two bars meet. Then we replace the bars with forces which diverge from the joint. Then we solve for the joint to be in equilibrium. Once we have done this, we can then find other joints
• Method of Sections:
  We cut through bars to create a section of the truss. Then we say that alll of the bars we cut through become diverging forces. Using this, we can then analyse the section with those forces and the external reactionary forces, because all of the internal forces will resolve to 0

Question 9

What is the equation of friction?

Answer 9

Friction = Friction Coefficient * Reactionary Force

Question 10

What is the path of a particle?

Answer 10

It is the direction that the particle will travel

Question 11

What is the velocity of a particle relative to the path?

Answer 11

The velocity is the time derivative of the path

Question 12

What is the acceleration of a particle relative to the velocity?

Answer 12

The acceleration is the time derivative of the velocity

Question 13

What is rectilinear motion?

Answer 13

Motion when the path is a straight line

Question 14

How is a = v * dv/dx?

Answer 14

a = dv / dt = dv / dt * dx / dx = dv / dx * dx / dt = v * dv / dx

Question 15

What is the displacement of a particle under rectilinear motion if a = 0?

Answer 15

x = (v * t) + x0

x0 is the original displacement

Question 16

What is the displacement of a particle under rectilinear motion if acceleration is constant?

Answer 16

x = (a0 * (t^2 / 2)) + v0 * t + x0

All terms with 0 are their initial values

Question 17

What is the displacement of a particle under rectilinear motion if acceleration is constant?

Answer 17

x = (a0 * (t^2 / 2)) + v0 * t + x0

All terms with 0 are their initial values

Question 18

What equation can be used to compare the initial and final velocity of a particle acting under rectilinear motion with a constant acceleration?

Answer 18

v^2 = u^2 + 2as

Question 19

Where does the velocity act in curvilinear motion relative to the path?

Answer 19

The velocity is always tangential to the path

Question 20

What is at and what does it represent?

Answer 20

at is the variation of the magnitude of velocity. It is equal to dv / dt and it acts tanential to the path

Question 21

What is an and what does it represent?

Answer 21

an is the variation of the direction of velocity. It is equal to v^2 / Radius and it acts normally to the path

Question 22

What is the equation for work?

Answer 22

W = s * F * cos(a)

Question 23

What is the equation of Kinetic Energy?

Answer 23

E = 1/2 * m * v^2

Question 24

What is the equation of work relative to kinetic energy?

Answer 24

W = 1/2 * m * (v^2 - u^2)

Question 25

What is a conservative field of forces?

Answer 25

This is a field where the work done only depends on the final and initial values of the particle, not the path of motion

Question 26

What is the equation for gravitational potential energy?

Answer 26

m * g * h

Question 27

What is the equation for elastic energy?

Answer 27

1/2 * k * s^2