Mechanics

Question 1

scalar

Answer 1

magnitude only

Question 2

vector

Answer 2

magnitude and direction

Question 3

moment equation

Answer 3

force x distance from pivot

Question 4

what is equilibrium

Answer 4

sum of clockwise moments=sum of anticlockwise moments

Question 5

what is a couple

Answer 5

2 coplanar forces of equal size acting parallel to each other but in different directions

Question 6

what is centre of mass

Answer 6

point on a body of mass with no turning effect

Question 7

suvat equations

Answer 7

v=u+at
s=0.5(u+v)t
s=ut+0.5at^2
v^2=u^2+2as

Question 8

what is terminal velocity

Answer 8

driving and resistive force constant

Question 9

Newton’s laws of motion

Answer 9

1. Velocity will not change unless force acts on it
2. Force = Mass x Acceleration
3. Every force has an equal and opposite reaction

Question 10

momentum equation

Answer 10

momentum = mass x velocity

Question 11

elastic vs inelastic collision

Answer 11

elastic - momentum and energy conserved
inelastic - energy not conserved

Question 12

Hooke’s law

Answer 12

F = k x l

Question 13

density

Answer 13

mass / volume

Question 14

elastic vs plastic

Answer 14

elastic - return to original shape
plastic - material permanently stretched

Question 15

stress and strain

Answer 15

Stress = F/A
Strain = Δl/l

Question 16

Young modulus

Answer 16

E=stress/strain
E=Fl/AΔl
The gradient of stress-strain graph is equal to Young Modulus

Question 17

questions with crumple zones

Answer 17

increased time of contact and increased stopping distance
reference work done = force x distance
reference to change in momentum