Forces Flashcards
Upthrust
Vertical upward force exerted on a body by a fluid when it is fully or partially submerged in the fluid due to the diff in fluid pressure
Hooke’s Law
The extension of a body is proportional to the applied force if the limit of proportionality is not exceeded
Pressure
Force per unit area, where the force is acting at right angle to the area
Achimedes’ Principle
Upthrust on a body in a fluid is equal to the weight of the fluid displaced by the body
Principle of floatation
For an obj floating in eqm, the upthrust is equal in mag and opp in direction to the weight of the obj
Eqn of spring force & Ek
F=kx & Ek=1/2 kx^2
If the spring is cut into half, what happens to k
k X 2
When springs are connected in series n parallel … value of k
//: k eff = k1 + k2 +... series: 1/k eff = 1/k1 + 1/k2 + ...
R/s b/w viscous force and speed (high n low speed)
Low speed Fv prop v
High speed Fv pro v^2
Conditions for forces to be in eqm
- Resultant force on the body in the system is 0
2. The resultant moment on the body abt any axis is 0
Translational eqm vs rotational eqm
translational: vector sum of forces must be 0
rotational: moments must be 0
Principle of moments
For a body in rotational eqm, the sum of all clockwise moments abt ant axis must equal to the sum of all the anticlockwise moments abt the same axis
Moment of a force/turning effect of a force
Defined as the prod of the force and the perpendicular dist of the line of action of the force from the axis
2 methods of finding moment of F abt the end of the rod
look at notes
Torque of a couple & eqn
Prod of the mag of 1 of the forces and the perpendicular dist b/w the forces & Torque = Fd
