7063083
Description
Flashcards by Talent Msipa, updated more than 1 year ago
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Created by Talent Msipa
about 8 years ago
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| Question | Answer |
| Name the SI unit for mass, length , time , temperature , electric current and amount of substance. | Kg, m ,seconds , kelvin , Amps , moles |
| Name the prefixes for Micro , tera , giga and mega . | 10^-6 , 10^12 , 10^9 , 10^6 |
| What is a scalar Quantity ? | A magnitude that consists of just the magnitude (size) |
| What is a vector quantity ? | a quantity that has both magnitude and direction |
| Name five scalar quantities ? | Density , Temperature , Pressure , Frequency and Power |
| Name five vector quantities ? | Displacement , Velocity , Acceleration , Force and momentum |
| What is speed ? | Speed is the distance over time |
| what is the unit for speed ? | ms^2 |
| What is acceleration ? | the rate in change in velocity |
| What is the difference between speed and acceleration? | Speed is a scalar quantity and acceleration is a vector quantity |
| What does a straight line in displacement time graph show ? | Constant velocity |
| What is instantaneous velocity ? | the gradient at any point of the displacement time graph |
| What is the area underneath speed time graphs? | Displacement |
| In the equations of motion what is represented by suvat ? | Displacement , initial velocity , final velocity , acceleration and time |
| What is free fall ? | downward movement under the force of gravity only |
| What is the numerical value for gravity ? | 9.81 ms^2 |
| What is force ? | strength or energy as an attribute of physical action or movement( push or pull) |
| What is gravitational force , magnetic force and electrical force ? | between two objects with a certain mass , between two magnetic objects and charged objects |
| what is the name of the force that combines electrical force and magnetic force ? | Electromagnetic force |
| Name the First Newton Law and what equation is associated with it ? | When an object has no resultant force on it , it wont accelerate it will stay at constant velocity , F=ma |
| What is weight , its equation ? | Gravitantional force on a body , W= mg |
| What is drag ? | its the resistive force the an object experiences when travelling through liquid |
| Terminal Velocity ? | this is when drag and air resistance reaches equilibrium on an object |
| What is the centre of gravity ? | a point where the entire weight of an object is considered to act as a single force. |
| What is a couple ? | It occurs when two forces are equal to each other and opposite to each other but not in a straight line |
| What is a torque ? | Used to describe the turning effect of a couple |
| Equation for torque ? | one of the forces * perpendicular distance between them (nm) |
| What is the principle of moments ? | in a rotation the sum of the clockwise moments is equal to the sum of the anticlockwise moments |
| Equation for moment ? | Fx ( f = force and x = perpendicular distance ) |
| What is Density ? | mass perunit volume and si unit = kgm^3 |
| What is pressure ? | Force per unit area (pascal ) |
| Equation to work out pressure in liquid ? | hpg (h=height , p = density and g = gravity ) |
| What is Thinking distance ? | Speed * reaction time |
| What is breaking distance ? | time taken from hitting the brakes to coming to a stop |
| What is stopping distance ? | thinking distance + breaking distance |
| Equation for car safety kinetic energy ? | breaking force * breaking distance |
| Name 3 things that increase crash time ? | seatbelts , crumple zones and air bags |
| What are crumple zones ? | a part of a motor vehicle, especially the extreme front and rear, designed to crumple easily in a crash and absorb the main force of an impact. |
| What are air bags ? | The airbag module is designed to inflate extremely rapidly then quickly deflate during a collision or impact with a surface or a rapid sudden deceleration. |
| Seat belts ? | secure the occupant of a vehicle against harmful movement that may result during a collision or a sudden stop. |
| What is the equation for work ? | work = force * distance |
| What is the conservation of energy ? | total energy in = total energy out (energy cannot be created or destroyed it can only be moved from state to state ) |
| What is gravitational potential energy ? | energy stored in an object by virtue of its position in a gravitational field |
| What is the equation for kinetic Energy ? | 1/2 mv^2 ( m = mass , v= speed ) |
| What is power ? | The rate of doing work |
| Equation for power ? | workdone / time taken |
| What is efficiency ? | the ratio of the useful work performed by a machine or in a process to the total energy expended or heat taken in |
| Equation for efficiency ? | useful output energy / total outpul energy *100 |
| What are sankey diagrams ? | Diagrams used to show the efficiency of energy |
| What are the two types of stretch ? | Elastic and plastic |
| What is Elastic stretch ? | when you stretch a material and it returns to its original form |
| What is plastic stretch ? | When a material becomes deformed , where it is permanently stretched |
| What are tensile forces ? | forces that stretch because they cause tension in the object |
| What are compressive forces ? | when you reduce the material`s length by squishing it (spring ) |
| What is elastic limit ? | is a point in a material where it has maximised its elasticity |
| What is plastic deformation ? | when an object wont return to its original shape |
| What is Hooke's law ? | the extension of the elastic body is proportional to the force that caused it |
| Equation for Hooke's law ? | F=Kx (x=extension k = for per unit ) |
| What is young modulus ? | The ratio between stress and strain |
| What is stress and strain ? | stress is the force per unit cross-sectional area (force / area ) Strain is extension per unit length |
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