Physics

what is a base quantity?

physical quantity that cannot be defined in terms of other quantities

what are the base quantities?

length, mass, time, temperature, electric current

difference between scalar and vector quantity?

scalar has magnitude only, vector has both magnitude and direction

define distance

total path taken by an object

define displacement

shortest distance and direction from an object’s initial position to its final position

define speed, state its formula

distance travelled per unit time, v=d/t

define velocity, state its formula

speed in a given direction, v=s/t

define acceleration, state its formula

change in velocity per unit time, a = final (v) - initial (u) / t

define deceleration

negative acceleration

how to calc average speed?

total distance travelled / total time taken

what does the gradient of a distance-time graph represent?

speed or velocity

what does the gradient of a speed-time graph represent?

acceleration

what does the area under speed-time graph represent?

distance travelled

how to find weight of an object?

mass * gravitational field strength

gravitational field strength definition, and formula

force per unit mass, gravitational force / mass

density definition, formula

mass per unit volume, m/V

Newton’s first law of motion states that

an object will continue its state of motion of rest or constant velocity unless acted on by an unbalanced force

Newton’s second law of motion states that

resultant force = mass * acceleration

Hooke’s law states that

the extension of an elastic object is directly proportional to the force applied, up to the limit of proportionality. F = spring constant (k) * extension (x)

define spring constant

force per unit extension; k = F/x

difference between x-F graph and F-x graph?

x-F graph: used for experiments; F-x graph: used for theory. F-x graph’s gradient means spring constant because k = F/x

define moment and its formula

product of force and perpendicular distance from the pivot, m = Fd

define centre of gravity

point through which the entire weight of an object is considered to act