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)
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Determination of ‘little-g’
One of my favourite experiments in GCSE physics is a practical that seems to have fallen from favour in recent years – but it’s still worth exploring. The experiment involves using a ticker-timer to make dots at regular time intervals (0.02 s apart) on a strip of tape that is attached to a moving object. … Continue reading Determination of ‘little-g’
Gamma Radiation
Of the three types of nuclear radiation discussed at GCSE level, gamma is definitely the unsung hero. Alpha and beta get plenty of limelight because they have both mass and charge, so they feature prominently in nuclear decay equations (as explained previously, here). But gamma radiation is a wave rather than a particle, so it … Continue reading Gamma Radiation
Examination Information
Many readers of this 'blog will not be sitting GCSE examinations this summer but for those of you who are, this is probably the most important piece of information you will read this year! AQA, which sets the Trilogy examination papers, has just released Advanced Information about the content of this summer's examinations: the document … Continue reading Examination Information
Slowing and Stopping
To conclude the recent series of posts related to different aspects of motion, we will now look at a real-world application of these ideas: in particular, the physics of slowing and stopping a road vehicle. An earlier post (from 2019) covered the two components of a vehicle’s overall stopping distance so I won’t repeat that … Continue reading Slowing and Stopping
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
Force and Acceleration
There are various techniques that can be used to investigate the relationship between force, mass and acceleration (Newton’s Second Law of Motion). In a school lab, we often use a dynamics trolley (wheeled platform) that is attached to a mass hanger via a string that runs over a desk pulley. The mass hanger provides the … Continue reading Force and Acceleration
Forces and Motion
Let’s get the common misconception out of the way first: moving objects do not remain in motion because there is a force that keeps them going. In fact, it’s the opposite. Moving objects always remain in the same state of motion unless an external force stops them. By “the same state of motion” we mean … Continue reading Forces and Motion
Acceleration and Distance
To find acceleration without measuring time, we can use a combination of the object's mean speed and distance-moved as a substitute for time. We already know that speed is calculated as distance divided by time, so we can rearrange this equation to calculate time as distance divided by speed. Of course, the speed of an … Continue reading Acceleration and Distance
Calculating Acceleration
Acceleration is the rate of change of speed (we will leave aside velocity for now) and that means we can calculate acceleration if we know the speed of an object at two different times. The object’s acceleration is given by its change in speed, divided by the time interval. Positive acceleration indicates that the object … Continue reading Calculating Acceleration
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