P2. Describing motion - Notes for IGCSE Coordinated Sciences PDF

Preview

Summary

Notes for IGCSE Coordinated Sciences...

Description

*Coordinates to IGCSE Coordinated Sciences SYLLABUS (0645)*

IGCSE - Coordinated Sciences (PHYSICS) STUDY GUIDE - P2 ● ● ● ● ● ● ● ● ● ● ● ●

● ● ● ●

● ● ● ● ● ● ● ● ● ● ● ● ● ●

Speed refers to the distance travelled by an object per unit time. Speed = distance/time Speed relies on the total distance travelled between two points and the total time taken to travel between those. Average speed = total distance/total time Unit for speed is m/s To measure the speed of an object in a lab you use light gates connected to an electronic timer. Light gates beam infrared radiation and when the beam is broken, the timer begins. When the other beam is broken, the timer stops and shows the time taken to travel the distance between both light gates. The interrupt card is what breaks the breams- the faster it is moving, the shorter time it takes to break the beam. Diagram P416 Worked example P418 Distance-time graphs show: graph sloping upwards meaning the object is traveling at a slow speed, graph becomes steeper meaning the object is accelerating, the graph is horizontal means there is no movement/distance is not changing. The steeper the graph, the faster it is going. Acceleration tells us the rate at which its velocity is changing. Deceleration tells us the rate at which its speed is changing- getting slower. Symbol g refers to the force at which an object accelerates free fall, meaning it is being pulled down by gravity. Speed-time graphs tell us how the object’s speed changes AS it moves. The steeper the slope, the greater the acceleration. A negative slope means deceleration. A horizontal slope means a constant speed. Speed at zero means the object has stopped moving. Distance = area under-speed time graph. Worked examples P421/22 Speed = gradient of distance-time graph. Rise/run to find the gradient. Acceleration = change in speed/time taken. Unit for acceleration is m/s^2 (a is used as the symbol). a = v - u/t Worked examples P423/24 Speed-time graphs: acceleration = gradient of speed-time graph.

● ●

Velocity is an object’s particular speed in a particular direction. Acceleration = change in velocity/time taken....