M2-careful with mistakes Watch
- Restitution: Care the directions of the particles, so that gives correct sign in the equations.
- Equillibrium: Care the perpendicular distance, not distance between 2 points
- Centre of mass: Care the sign of coordinates, I mean when 2 points at the different side of the axis(line) they have different signs.
What else did u find out? Plz remember them when u r sitting on the exam
(Read the question!)
Don't see velocity if it says speed.
mv for momentum
HALF m vSQUARED for KE
resolve 2 directions and moments about 1 point or
resolve 1 direction and moments about 2 points
Check to see if you've got both the normal reactions in you ladder sketch!
[These were the basis of my favourite mistakes]
That one was important in 6B and 6C today
Another mistake which could have been easy made today is calculating the correct expression for an impulse. Impulse can be commonly denoted by m(v-u), but in the situation today the particles had 2m and 3m, so m had to be replaced by the corresponding mass.