Mechanics - module 3 Flashcards
What is meant by drag?
An object moving through a fluid experiences a drag force acting on it. Drag is a frictional force that opposes motion
What it meant by terminal velocity?
The maximum speed reached by an object when the drag force on it is equal and opposite to the force causing the motion of the object.
What are factors that can affect drag?
- viscosity of the fluid an object is travelling in.
- The speed of the object. Drag increases as speed increases.
- Shape and size of the object
What are frictional forces?
- Always act in opposite direction to the motion of an object
- Can never speed things or start moving something
- Convert kinetic energy to heat energy.
what is moment?
force x perpendicular distance of the line of action of force from the axis
what is the principle of moments?
-for a body in rotational equilibrium, the sum of the anticlockwise moments about any point is equal to the sum of the clockwise moments about that same point.
what is torque?
- the moment of a couple is known as a torque.
- torque of a couple = one of the forces x perpendicular separation between forces.
what is archimedes principle?
-the upthrust exerted on a body immersed in a fluid, wheter fully or partially submerged, is equal to the weight of the fluid that the body displaces.
what is upthrust?
the upward buoyant force exerted on a body immersed in a fluid.
what is pressure?
-the normal force exerted per unit cross sectional area.
what is work done?
-force x distance moved in the direction of the force.
work done = energy transferred
what is the principle of conservation of energy?
-the total energy in a closed system remains constant: energy can never be created or destroyed but only transferred between forms.
