mechanics definitions

Question 1

scalar quantity

Answer 1

a scalar quantity is one with magnitude only. It has no direction

Question 2

distance

Answer 2

the distance between 2 points is a measure of how far one point is from the other

Question 3

time

Answer 3

time is used to measure the duration of events, to put them into sequence or to measure the interval between them

Question 4

speed

Answer 4

speed is distance travelled per unit time

Question 5

vector quantity

Answer 5

a vector quantity is one with both magnitude and direction

Question 6

displacement

Answer 6

displacement is distance in a given direction

Question 7

velocity

Answer 7

velocity is the rate of change of displacement with respect to time

Question 8

acceleration

Answer 8

acceleration is the rate of change of velocity with respect to time

Question 9

mass

Answer 9

mass is a measure of the amount of matter in a body

Question 10

momentum

Answer 10

momentum is the product of mass and velocity
momentum=mass x velocity

Question 11

force

Answer 11

a force is that which can cause acceleration

Question 12

acceleration due to gravity

Answer 12

acceleration due to gravity is the acceleration experienced by a body in free fall within the gravitational field of a massive body

Question 13

weight

Answer 13

weight is force equal to the product of mass and acceleration due to gravity
w=mg

Question 14

centre of gravity

Answer 14

centre of gravity is the point at which all of the weight appears to act

Question 15

friction

Answer 15

friction is a force that opposes the motion of a body

Question 16

moment of a force

Answer 16

the moment of a force is the force multiplied by the perpendicular distance to the fulcrum
M=Fd

Question 17

lever

Answer 17

a lever is a rigid body that is free to rotate about a fixed point called the fulcrum

Question 18

couple

Answer 18

a couple is a pair of equal and opposite forces whose lines of action do not concide

Question 19

torque

Answer 19

the torque of a couple is equal to the magnitude of one of the forces multiplied by the distance between them
T=Fd

Question 20

density

Answer 20

density is mass per unit volume
d=m/v

Question 21

pressure

Answer 21

pressure is force per unit area
P=F/A

Question 22

buoyancy

Answer 22

buoyancy is the upward force on a body that is partially immersed in a fluid

Question 23

work

Answer 23

work is the product of force and displacement
W=Fs

Question 24

energy

Answer 24

energy is the ability to do work

Question 25

kinetic energy

Answer 25

kinetic energy is the energy a body has due to its motion

Question 26

potential energy

Answer 26

potential energy is the energy a body has due to its position

Question 27

power

Answer 27

power is the rate at which work is done

Question 28

angular velocity

Answer 28

angular velocity is the rate of change of angle

Question 29

angle

Answer 29

angle measured in radians, is equal to the arc length divided by the radius

Question 30

linear velocity

Answer 30

linear velocity is the speed of the particle in a direction perpendicular to the radius at that point

Question 31

periodic time

Answer 31

periodic time is the time taken for one complete revolution, cycle or oscillation

Question 32

centripetal acceleration

Answer 32

centripetal acceleration is the acceleration of an object travelling in uniform circular motion, it is directed toward the centre of the circle

Question 33

centripetal force

Answer 33

centripetal force is the force required to maintain uniform circular motion , it is directed toward the centre of the circle

Question 34

elastic constant

Answer 34

the elastic constant is the constant of proportionality between the applied force and the resulting displacement of a given spring

Question 35

elasticity

Answer 35

elasticity is the ability of a body to resist a distorting influence or stress and to return to its original size and shape when the stress is removed

Question 36

simple harmonic motion

Answer 36

simple harmonic motion is where the acceleration of a body towards a particular point is proportional to displacement from that point

Question 37

frequency

Answer 37

frequency is the number of oscillations the object completes per unit time

Question 38

period

Answer 38

the period of a particle executing SHM is the time taken for one complete oscillation