Mechanics Flashcards
Random errors
Random errors are errors in measurements that lead to measured values being scattered unpredictably about a mean.
Systematic errors
Systematic errors are errors which lead to all measured values being either consistently greater or consistently lesser than the true value by a fixed value.
accuracy
The accuracy of a set of experimental data is defined as a measure of how close the experimental values are to the true value of the physical quantity.
precision
The precision of an experiment is defined as a measure of how close the experimental values are to each other.
scalar
A scalar is a physical quantity that is completely specified by a value with an appropriate unit and has no direction.
vector
A vector is a physical quantity that is completely specified by a value with an appropriate unit and that has direction.
speed, velocity, acceleration
rate of change of distance travelled; rate of change of displacement; rate of change of velocity
Hooke’s Law
Hooke’s law states that the extension x is directly proportional to the force F applied on the spring or wire (provided the limit of proportionality is not exceeded).
Upthrust
Upthrust U is the resultant vertical upward force exerted by the surrounding fluid on a fully or partially submerged body as the pressure at the bottom surface is greater than that at the top.
Archimedes’ Principle
Archimedes’ Principle states that when a body is wholly or partially immersed in a fluid, it is buoyed by an upthrust equal in magnitude and opposite in direction to the weight of fluid displaced by the body.
Principle of Floatation
Principle of Floatation states that when a body is floating in equilibrium in a fluid, the upthrust on it is equal in magnitude to the weight of the body.
CG (Centre of Gravity)
Centre of gravity of a body is the point where the weight of the body appears to act through.
Moment of a force
Moment of a force about a point is defined as the product of the magnitude of force F and the perpendicular distance d of the point from the line of action of the force.
Torque of a couple
Torque of a couple is defined as the product of one of the forces F and the perpendicular distance d between the lines of action of the forces, where the forces are equal in magnitude and opposite in direction and their lines of action do not coincide.
(Static) equilibrium
Static equilibrium occurs when resultant force is zero in all directions and resultant torque is zero about any axis.
Principle of Moments
Principle of moments states that if a body is in equilibrium, the sum of clockwise moments must be equal to the sum of anti-clockwise moments about any point.
Linear momentum
The linear momentum p of a body is defined as the product of its mass m, and its velocity v and it is in the direction of the velocity.
N1L
Newton’s First Law of Motion states that a body continues to be in a state of rest or uniform motion in a straight line (uniform velocity) unless acted on by a net external force.
N2L
Newton’s Second Law of Motion states that the rate of change of momentum of a body is directly proportional to the net external force acting on it and it takes place in the direction of the net external force.
N3L
Newton’s Third Law of Motion states that if a body A exerts a force on body B, then body B exerts a force of the same type (nature) of equal magnitude but opposite in direction on body A.
weight
The weight of an object is defined as the resultant gravitational force acting on it due to gravitational field of (massive object). Given by mg.
Conservation of Momentum (COM)
The principle of conservation of momentum states that the total momentum of a system remains constant before, during and after a collision provided that no net external force acts on the system.
Work Done (WD)
The work done by the constant force is defined as the product of the force and displacement in the direction of the force.
Power
Rate of work done
Angular displacement
The angular displacement is the angle subtended at the centre of a circle in radians by arc length s in the anti-clockwise direction where it is equal to s/r with r being the radius of the circle.
Angular velocity
rate of change of angular displacement
Field (of force)
A field of force is a region of space where an object, with a property unique to that field, experiences a force.
Newton’s Law of Gravitation
Newton’s law of gravitation states that **every point mass attracts every other point mass **with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between them.
Graviational field strength
Gravitational field strength at a point is defined as the gravitational force exerted per unit mass on a small test mass placed at that point in the gravitational field.
Gravitational Potential Energy (GPE)
Gravitational potential energy of a system of masses is defined as the work done by an external agent in bringing the masses from infinity to their positions in the system, without producing any acceleration.
Gravitational Potential
Gravitational potential at a point in a gravitational field is defined as the work done per unit mass by an external agent in bringing a small test mass from infinity to that point, without producing any acceleration.
escape velocity
The escape velocity is defined as the minimum initial velocity of any object that just allows the object to escape a planet’s (or any large celestial body’s) gravitational field and never return to the planet’s surface.
Geostationary orbit
A geostationary orbit is one where the satellite will remain in the same position in the sky relative to the Earth’s surface.
