# Fundamental Concepts Tutorial 1 to answer just click on the button or image related to the answer.

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Fundamental Concepts Tutorial 1 to answer just click on the button or image related to the answer

A. FUNDAMENTAL CONCEPTS

what is their weight (in kN) on earth ? (on Earth g = 10 m/s 2 approx) a person has a mass of 70 kgs. Question A1 700 kN a 0.7 kN b 70 kN c

what is their weight (in kN) on a roller coaster ? (on roller coaster g rc = 3 x g m/s 2 approx) a person has a mass of 70 kgs. Question A2 2.1 kN a 210 kN b 21 kN c

what is their weight (in kN) on the moon ? (on the moon g m = 0.17 x g m/s 2 approx) a person has a mass of 70 kgs. Question A3 1.2 kN a 120 kN b 0.12 kN c

what is the force acting down on surface S ? given two blocks A, and B on a surface S. Question A4a 200 kN a 3 kN b 300 kg c A B S mass (A) = 100kg mass (B) = 200kg

what is the force acting up on block B ? given two blocks A, and B on a surface S. Question A4b 2 kN a 3 kN b 1 kN c A B S mass (A) = 100kg mass (B) = 200kg

what is the pressure on surface S ? given two blocks A, and B on a surface S and that block B is 200 x 150 mm Question A4c 66.6 Pa a 1000 kPa b 100 kPa c A B S mass (A) = 100kg mass (B) = 200kg

what is the moment at A ? given the force of 2kN acting as shown Question A5a 5 kNm a 10 kN/m b 10 kNm c B A C 5m 2kN 3m

what is the moment at B ? given the force of 2kN acting as shown Question A5b 6 kNm a 3 kN/m b 1.5 kNm c B A C 5m 2kN 3m

what is the moment at C ? given the force of 2kN acting as shown Question A5c 2 kNm a 2 kN/m b 0 kNm c B A C 5m 2kN 3m

what have we learnt ? so in general, if a point lies on the line of action of a force Question A5d nothing a the moment of a force about a point lying on the line of action of the force is zero b

which system of forces will provide equilibrium? given the system shown Question A6 ab 10kN 14.1kN either a or b c

find forces F2 and R1 so as to provide equilibrium? given the system shown Question A7 F2= ? kNF1= 12kN ABC 3m1m R1= ? kN F2 = 4 kNm and R1 = 16 kNm a F2 = 4 kN and R1 = 16 kN b F2 = 36 kN and R1 = 48 kN c

B. GENERAL PRINCIPLES

what is the purpose of structure in buildings? Question B1 to provide the fabric of the space enclosure a to organize the elements of the building b to resist all the forces acting on the building and transfer them to supports (the ground) c all of the above d a and c e

what are the three main considerations when dealing with structure? Question B2 aesthetics, spaces and materials a stability, strength and stiffness b dead loads, live loads and supports c

Question B3 show answer a finish b given the post-and beam arrangement as shown, and assuming pin-joints, describe three ways of stabilising it. draw and name them

let me try again let me out of here Weight is a force. Weight = Mass x g where g = 10 m/s 2 on earth 1kg of mass = 10N of force on earth. 100kg of mass = 1kN weight on earth

next question enough ! Weight is a force. Weight = Mass x g where g = 10 m/s 2 on earth 1kg of mass = 10N of force on earth. 100kg of mass = 1kN weight on earth 0.7 kN so on Earth (g = 10 m/s 2 ) Weight = 70 x 10 /1000 =

next question enough ! Weight is a force. Weight = Mass x g where g = 10 m/s 2 on earth and 30 m/s 2 on a roller coaster 1kg of mass = 30 N of force on roller coaster. 100kg of mass = 3 kN weight on roller coaster 2.1 kN so on roller coaster (g = 30 m/s 2 )Weight = 70 x 30 /1000 =

let me try again let me out of here Weight is a force. Weight = Mass x g where g = 10 m/s 2 on earth and 30 m/s 2 on a roller coaster 1kg of mass = 30 N of force on roller coaster. 100kg of mass = 3 kN weight on roller coaster

next question enough ! Weight is a force. Weight = Mass x g where g = 10 m/s 2 on earth and 1.7 m/s 2 on the moon 1kg of mass = 1.7N of force on the moon. 100kg of mass = 0.17kN weight on the moon 0.12 kN so on the moon (g = 1.7 m/s 2 )Weight = 70 x 1.7 /1000 =

let me try again let me out of here Weight is a force. Weight = Mass x g where g = 10 m/s 2 on earth and 1.7 m/s 2 on the moon 1kg of mass = 1.7N of force on the moon. 100kg of mass = 0.17kN weight on the moon

next question enough ! both blocks A and B are acting on surface S 3000 N so the total weight on surface S (on earth) = (100 +200) x 10 = 3 kN =

let me try again let me out of here both blocks A and B are acting on surface S don’t forget that it’s force we are after, not mass you must convert the total mass to a force

next question enough ! for every force there is an equal and opposite reaction since the total force acting down is 3 kN, the force acting up, i.e. the reaction must be 3kN

let me try again let me out of here remember: for every force there is an equal and opposite reaction

next question enough ! pressure = force / area, P = F / A so, working in kNs and metres, P = 3 / (0.2 x 0.15) = 100 kN/m 2 since 1 kN/m 2 = 1 kPa, 100 kN/m 2 = 100 kPa

let me try again let me out of here pressure = force / area, P = F / A so think about what the total force down is and what the area is. work in kNs and metres

next question enough ! moment = force x distance, M = F x D yep! moment is force x distance, so the moment is 2 x 5 = 10 kNm since it is force x (multiplied by) distance the units are kN x m, i.e kNm

let me try again let me out of here so think what the force is and what the distance is. The distance is the perpendicular distance from the point to the force work in kNs and metres moment = force x distance, M = F x D

let me try again let me out of here so think what the units are force multiplied by – not divided by distance moment = force x distance, M = F x D

next question enough ! moment = force x distance, M = F x D yep! moment is force x distance, so the moment is 2 x 3 = 6 kNm since it is force x (multiplied by) distance the units are kN x m, i.e kNm

let me try again let me out of here so think what the force is and what the distance is. The distance is the perpendicular distance from the point to the force Think of the units. Work in kNs and metres moment = force x distance, M = F x D

next question enough ! moment = force x distance, M = F x D yep! moment is force x distance, so the moment is 2 x 0 = 0 kNm since it is force x (multiplied by) distance the units are kN x m, i.e kNm

let me try again let me out of here so think what the force is and what the distance is. The distance is the perpendicular distance from the point to the force Think of the units. Work in kNs and metres moment = force x distance, M = F x D THINK !!

next question enough ! moment = force x distance, M = F x D so if the point lies on the line of action of the force, the distance from the point to the force must be 0 and hence the moment must be 0

let me try again let me out of here so think what the distance is when the point lies on the line of action of the force. moment = force x distance, M = F x D

next question enough ! in a) the vertical forces are equal and opposite and the horizontal forces are equal and opposite in b) the resultant force of the horizontal and vertical forces would be 14.1 kN, so the equilibrant force (the force providing equilibrium) would be 14.1 kN (equal and opposite to the resultant force) both systems are in equilibrium

let me try again let me out of here the vertical forces are equal and opposite and the horizontal force are equal and opposite so it is in equilibrium but this is not quite the right answer

let me try again let me out of here the equilibrant force is equal and opposite to the resultant force of the horizontal and vertical forces so it is in equilibrium but this is not quite the right answer

next question enough ! clockwise moments about B = 12 x 1 = 12 kN anti-clockwise moments about B = F2 x 3 so F2 x 3 = 12 kN  F2 = 4 kN since ΣV = 0, R1 = 4 + 12 = 16 kN

let me try again let me out of here THINK !! what are the units for forces?

let me try again let me out of here take clockwise moments about B, then take anti-clockwise moments about B then use the equation ΣM = 0 (sum of clockwise = sum of anti-clockwise) How did you get this? Don’t guess!!

next question enough !

let me try again let me out of here that’s part of the answer – what else is there?

let me try again let me out of here in general terms, structure does deal with the organization of complex objects but we are concerned with structure in the domain of forces

let me try again let me out of here How did you get this? Don’t guess!!

next question enough ! Stability - equilibrium building must not move - up, sideways or overturn all forces and moments must balance Strength building & elements must not break / collapse Stiffness / functionality building & elements must continue to serve their purpose, must not deform too much the three S s

let me try again let me out of here we are concerned with structure in the domain of forces not with architectural form or spaces

let me try again let me out of here these are concerns - but they are not the main general concerns

l a) cross-bracing l b) knee-bracing l c) rigid joints l d) solid infill (shear panels) l e) build-in posts any of these will do that’s it