Having looked at the first Physics paper for this year's AQA Trilogy examination, it seems to me that a significant proportion of questions have been framed around situations and applications rather than just recalling and connecting facts. With that in mind, let's take a real-world look at motion along a line... First an important definition. … Continue reading Motion Along a Line
Contact and Non-Contact Forces
It is surprisingly hard to say what a force really is but on a simple level we say that forces are either pushes or pulls. It would be better to label "pulls" as forces of attraction and "pushes" as forces of repulsion. Some forces have their effect when objects are in contact whereas others allow … Continue reading Contact and Non-Contact Forces
Resolving Vectors
Having covered the basics of resultant forces, we can progress to a method for analysing vectors that does not rely purely on scale drawings. Before proceeding, let me stress that this approach is not needed for GCSE Physics but the method should be accessible to mathematically inclined readers and will prove very useful in post-GCSE … Continue reading Resolving Vectors
Resultant Forces (part 3)
In the final part of this mini-series, we have to deal with situations where the two component forces are neither opposite nor at right angles; the forces are simply at some general angle to each other. Typical situations where this could apply in real life are tugs pulling a ship or an airplane flying through … Continue reading Resultant Forces (part 3)
Resultant Forces (part 2)
In the first part of this mini-series we looked at forces that act in exactly opposite directions. We noted that although these forces can be subtracted, the correct procedure is to combine the forces in more rigorous way that clearly takes account of both their magnitude and their direction. The most powerful way to do … Continue reading Resultant Forces (part 2)
Resultant Forces (part 1)
The principle of resultants states that when two or more forces act on an object, they can be replaced with a single force that has the same effect as the multiple forces combined. This is a fairly simple idea but putting it into practice can produce a lot of confusion so let’s start with a … Continue reading Resultant Forces (part 1)
Momentum
Newton's Second Law of Motion tells us that the force required to accelerate an object can be calculated by multiplying the mass of the object by the acceleration that is required (F=ma). We also know that acceleration is simply the rate of change of velocity (the change in velocity divided by the time taken for … Continue reading Momentum
Speed and Velocity
In many situations, the word “speed” is used when in fact “velocity” would sometimes be more appropriate. Speed is the rate of change of distance: the word “rate” indicates time, so speed is simply a measure of how much the distance changes in each second of movement. If you took 80 seconds to run 400 … Continue reading Speed and Velocity
Compare and Contrast
A really useful revision tactic (and also quite a common type of exam question) involves looking at the differences that exist between two related things in the same area of physics. These comparisons can be very simple, such as the definitions of scalars and vectors, or they can be more complicated, such as competing theories … Continue reading Compare and Contrast
Electric fields
A field, in physics, is a region of space where one object can affect another object without the two objects touching each other. The most familiar fields are gravitational and magnetic but now we need to gain some understanding of electric fields and their shapes. Let's start with a quick recap of what we know … Continue reading Electric fields
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