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24 Cards in this Set
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1.1: Length and Time 
Ruler: Used to measure lengths for distances between 1mm and 1m. To find the volume of a regular object, you can use a mathematical formula, you just need to make a couple of length measurements. 

Measuring cylinders 
To measure the volume of an irregular object, you have to put the object into measuring cylinder with water. When you add the object, it displaces the water, making the water level rise. Measure this rise to give the volume of the object. 

Micrometers 


Time 
An interval of time is measured using clocks. To find the amount of time it takes a pendulum to make a spin, time ~25 circles and then divide by same number as the number of circles. 

1.2: Motion 
Average speed equation: total distance/total time Acceleration: change in velocity/time taken 

Definitions 
Speed: Distance travelled per unit time. Velocity: The rate of increase of distance travelled in a specified direction with time. 

Speed/Time Graph 
A straight horizontal line means that speed is constant. If the line is increasing, the moving object is accelerating. If the line is decreasing, it means the moving object is decelerating. 

Distance/Time Graph 
Time is increasing to the right, but its distance does not change, so it is at rest. The time and distance is increasing constantly, so it moves at a constant speed. 

Summary 


Acceleration 
An increase in speed is a positive acceleration.
A decrease in speed is a negative acceleration/ deceleration. If the acceleration isn't constant, the line on the graph will be curved. 

Acceleration and Gravity 
The downward acceleration of an object is caused by gravity. This happens most when an object is in free fall. Objects are slowed down by air resistance. Once the air resistance is equal to the force of gravity, the object has reached terminal velocity. This means that it will stay at a constant velocity. 

Gravity 
The value of gravity on Earth is 9.81m/s2. However, 10m/s2 is used in most calculations. Gravity= 2 x height dropped/ (time)2 g=2h/t2 This only works when there is no air resistance, so a vacuum chamber is required. 

1.3: Mass and Weight 
Mass: The property of an object that is a measure of its resistance to accelerate, the amount of matter it contains and its influence in a gravitational field. Weight: It is the force of gravity acting on an object, measured in Newtons, and given by this formula: Weight= mass x acceleration due to gravity. Weights may be compared using a balance. 

1.4: Density 
To determine the density of a liquid place a measuring cylinder with some liquid. The change in mass is the mass of the liquid and the volume is shown on the sale, then use this formula: Density= mass/volume To determine the density of an object, you use the methods used in 1.1 to find the volume and then weigh the object and use the formula. 

1.5: Forces (i) Effects of forces 
A force may produce a change in size and shape of a body, give the acceleration or deceleration or a change in direction depending on the direction of the force. 

Extension/Load Graph 


Experiment 
Finding the resultant force of two or more forces acting along the same line: 

Experiment Continued 


Hooke's Law 
Hooke's law: Springs extend in proportion to load, as long as they are under their proportional limit. Equation: Load (N) = spring constant (N/mm) x extension (mm) F=kx 

Definitions 
Limit of proportionality: Point at which load and extension are no longer proportional. Elastic limit: Point at which the spring will not return to its original shape after being stretched. Force = mass x acceleration 

Newtons 
Forces are measured in Newtons. 1 Newton is the amount of force needed to give 1kg an acceleration of 1m/s2 (if you think about it using the equation it's really obvious: if force = mass x acceleration, then 1 Newton = 1kg x 1m/s2) 

Circular Motions 
An object at a steady speed in a circular orbit is always accelerating as its direction is changing, but it gets no closer to the centre. 

Centripetal force 
This is the force acting towards the centre of a circle. It is a force that is needed (not caused by) a circular motion, e.g.: when you swing a ball on a string round a circle, the tension of the string is the centripetal force. If the string is cut, then the ball will travel in a straight line at a tangent to the circle at the point where the string was cut (Newton's first law). 

Centrifugal force 
This is also know as the nonexistent force is the force acting away the centre of a circle. This is what makes a slingshot go outwards as you spin it. The centrifugal force is the reaction to the centrifugal force (Newton's third law). It has the same magnitude, but opposite direction to the centrifugal force ("equal but opposite"). centripetal force = mass x velocity2 / radius. 