Forces Flashcards
Hooke’s law
Extension/compression of a body is proportional to the force applied on it, provided that the limit if proportionality is not exceeded.
Fluid pressure P at a point in the fluid
hpg
Define upthrust
The upward force exerted by a fluid on a submerged or floating object. It arises due to the difference in pressure between the upper and lower surfaces of the object.
It is equal in magnitude and opposite in direction to the weight of the fluid displaced by the object.
Define principle of floatation
When an object floats in equilibrium, upthrust is equal to the weight of the object
Define the moment of a force
The moment of a force about a point is the product of the force and the perpendicular distance from the line of action of the force to that point.
The torque of a couple is
the product of one of the force and the perpendicular distance between the forces
A body is in equilibrium if
The resultant force on any direction and torque on the body is zero
Principle of moments
Principle of moments states that for a body in equilibrium, the sum of clockwise moments about any point is equal to the sum of anti-clockwise moments about the same point.
Formula for upthrust
U= Vpg, V = volume, p = density
Define gravitational force
An attractive force exerted by one mass on another. Experienced by a mass when it is placed in a gravitational field of another mass.
Define electric force. (For forces)
A force exerted by one charge on another. Experienced by a charge when it is placed in an electric field of another charge.
Define magnetic force.
A force on a moving charge or a current carrying conductor in a magnetic field.
Define normal contact force.
The force that one body exerts on another body when they are in physical contact, perpendicular to the surfaces in contact.
Define frictional force
Frictional force arises when the surfaces in contact are rough. This force resists motion or the tendency of motion of a body.
Define viscous/drag force
Viscous or drag force is a resistive force that opposes motion of an object through a fluid.
