Forces & WEP Flashcards Preview

A Level Physics > Forces & WEP > Flashcards

Flashcards in Forces & WEP Deck (17):
1

Hooke's law

States that the force is directly proportional to the extension in a material if its limit of proportionality is not exceeded
F=kx
(Note: F against x graph must pass through origin to be directly proportional)

2

Difference between springs connected in parallel and series

Parallel: k=k1+k2
Series: 1/k=1/k1 +1/k2

3

Center of gravity

Point at which the whole weight of a body may be thought to act

4

Moment

Turning effect of a force. Moment of a force is equal to the product of the force and the perpendicular distance of the line of action of the force from pivot O

5

Torque of couple

Product of one of the forces F and the perpendicular distance d between the lines of action of the forces

6

Principle of moments

States that if a body is in equilibrium, the sum of all the clockwise moments about any axis must equal the sum of all the anticlockwise moments about the same point

7

Conditions for static equilibrium

Either translational equilibrium: Resultant force=0
Or rotational equilibrium: Resultant torque=0

8

How to check if system is equilibrium

All forces intersect at a common point, and the directions of the forces are either clockwise or anticlockwise in a closed shape like triangle

9

Density

Mass per unit volume

10

Pressure

Force per unit area, where force is acting at right angles to the area
(p=F/A)
p=ro gh

11

Archimedes' principle

States that when a body is totally or partially immersed in a fluid, the upthurst is equal to the weight of fluid displaced

12

Principle of flotation

States that for an object floating in equilibrium, the upthrust is equal to the weight of the object

13

Equations for pressure vs upthrust

Pressure(Pa) =ro gh
Upthrust(N)=V ro g
=ro gh x A

14

Work done

Product of a force and the displacement in the direction of the force
(Area under F-x graph)

15

What must remain constant when use W=p x deltaV

Pressure of the surroundings

16

Principle of conservation of energy

States that energy can neither be created nor destroyed in any process. It can be transformed from one form to another, and transferred from one body to another but the total amount remains constant

17

Power

Rate of doing work
(P=Fv)