Mechanics and waves Flashcards
What is the centre of gravity
A point on the object where gravity appears to act generally in the middle but not always
Why is a tall glass easily toppled
It is easily toppled when the line of action of its weight is beyond the edge of the base then the glass tips right over
Definition of moment
The product of the force * the perpendicular distance from the pivot
What is the eqaution for moments
Moments = FD
What is the pivot point
The point of Whitchurch an object rotates about
How do you know when an object is equilibrium
When the sum of clockwise moments equals the sum of anti-clockwise moments and there is no resultant force
How would you calculate the centre of mass of a piece of card
Hang up the card and suspend a plumb line from the same place
Mark the position of the thread
Repeat the above steps with the card suspended from different places
Where these lines intersect is the centre of mass
Definition of equilibrium
No resultant force
No resultant moment
What is the eqaution for momentum
P = mass * velocity
How do you work out velocity.
Total distance / total time
How do you work out GPE
GPE = MGH
How do you work out Ke
1/2 Mvsqaured
What is a scalar measurement
An amount just with a magnitude
Energy work done
Distance around a circle
What is vector measurement
An amount with a direction
Distance you are form the start of circle
What is an example of a scalar measurement
Speed
What are examples of vector measurements
Displacement
Force
velocity
Acceleration
What is the change in momentum also called
An impulse
How can you calculate F
F= impulse/time