Fundamental Concepts

Fundamental Concepts Tutorial 1 to answer just click on the button or image related to the answer let's go !!

FUNDAMENTAL • CONCEPTS continue

700 kN 0.7 kN 70 kN what is their weight (in kN) on earth ? a b c Question A1 a person has a mass of 70 kgs. (on Earth g = 10 m/s2approx)

2.1 kN 210 kN 21 kN a b c Question A2 a person has a mass of 70 kgs. what is their weight (in kN) on a roller coaster ? (on roller coaster grc = 3 x g m/s2approx)

1.2 kN 120 kN 0.12 kN a b c Question A3 a person has a mass of 70 kgs. what is their weight (in kN) on the moon ? (on the moon gm = 0.17 x g m/s2approx)

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

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

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

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

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

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

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

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

F2= ? kN F1= 12kN F2 = 4 kNm and R1 = 16 kNm F2 = 4 kN and R1 = 16 kN A B C 3m 1m F2 = 36 kN and R1 = 48 kN b a c Question A7 R1= ? kN given the system shown find forces F2 and R1 so as to provide equilibrium?

B. GENERAL PRINCIPLES continue

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

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

show answer finish a b Question B3 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 Oops Weight is a force. Weight = Mass x g where g = 10 m/s2 on earth 1kg of mass = 10N of force on earth. 100kg of mass = 1kN weight on earth

Weight is a force. Weight = Mass x g where g = 10 m/s2 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/s2) Weight = 70 x 10 /1000 = enough ! you've got it it!! next question

enough ! Fantastic Weight is a force. Weight = Mass x g where g = 10 m/s2 on earth and 30 m/s2 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/s2) Weight = 70 x 30 /1000 = next question

let me try again let me out of here Sorry Weight is a force. Weight = Mass x g where g = 10 m/s2 on earth and 30 m/s2 on a roller coaster 1kg of mass = 30 N of force on roller coaster. 100kg of mass = 3 kN weight on roller coaster

enough ! yipee! Weight is a force. Weight = Mass x g where g = 10 m/s2 on earth and 1.7 m/s2 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/s2) Weight = 70 x 1.7 /1000 = next question

let me try again let me out of here Oops Weight is a force. Weight = Mass x g where g = 10 m/s2 on earth and 1.7 m/s2 on the moon 1kg of mass = 1.7N of force on the moon. 100kg of mass = 0.17kN weight on the moon

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 = enough ! that's grrr..eat !! next question

let me try again let me out of here Don't cry 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

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 enough ! Celebrations next question

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

enough ! you've got it it!! pressure = force / area, P = F / A so, working in kNs and metres, P = 3 / (0.2 x 0.15) = 100 kN/m2 since 1 kN/m2 = 1 kPa, 100 kN/m2 = 100 kPa next question

let me try again let me out of here Sorry 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

enough ! Fantastic 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 next question

let me try again let me out of here Don't tell anyone! moment = force x distance, M = F x D 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

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

enough ! you've got it it!! 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 next question

let me try again let me out of here Not correct moment = force x distance, M = F x D 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

enough ! let's party !! 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 next question

let me try again let me out of here Come on .... THINK !! moment = force x distance, M = F x D 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

enough ! that's grrr...eat !! 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 next question

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

enough ! you've got it it!! both systems are in equilibrium 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) next question

let me try again let me out of here Almost 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 Almost 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

enough ! Amazing !! 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 next question

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

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

enough ! well done !! next question

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

let me try again let me out of here Well, ... No ! 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 Not right ! How did you get this? Don’t guess!!

the three Ss enough ! Magnificent !! 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 next question

Fundamental Concepts