For a while recently I've been interested in improving education, partly because it has been (arguable through little choice of my own) most of my life for twenty years. Also in part because I believe a good education may spark interest in the whole universe, increase understanding and empathy and lead to a more fulfilling life.
I have been told I am a man with my fingers in a lot of pies, but I have always been fascinated to learn how things work. This is why I decided to study physics at university. I'd like now to try my best to help others understand a topic which has been so beneficial to myself.
In our sessions
I'm not Derren Brown but I would like to see what makes you tick. Bring me the ideas or problems that trouble you most, and we will find out how you can best engage with those concepts. My goal is to have you be able to teach me. (The goal is obviously for you to sit exams unfortunately but I prefer mine). I will use analogy, diagrams and visual media to help concepts become familiar to you. You'll find then that answering questions is no longer a horrible chore. I mean it is but less so.
Okay what now?
If you feel after reading this that you'd like to meet me or ask some questions, request a meet the tutor session or send me a webmail through mytutorweb. Let me know what exam board you're studying for and what particularly you are struggling with. I'm looking forward to meeting you!
|Electronics||A Level||£20 /hr|
|Maths||A Level||£20 /hr|
|Physics||A Level||£20 /hr|
A particle with electric charge q, mass m and velocity v in a constant magnetic field B experiences a force due to the field:
F = qv X B
The 'X' (cross-product) means that the force is always at 90° (perpendicular) to both the velocity and magnetic field.
If v and B point along the same line (parallel or antiparallel), the particle feels no force. Otherwise it will feel a force and accelerate (change in velocity). But acceleration doesn't necessarily mean change in speed.
Because the force is perpendicular to the velocity (direction of travel), the particle's velocity changes only in direction. The speed (magnitude of the velocity) of the particle does not change.
Work is defined as the force F applied to the particle times the distance s over which is it applied in the same direction.
W = Fs
(technically, W = ∫ F • ds but they took the fun out of A level physics, eh?)
Since the magnetic force is always perpendicular to the direction of travel, and hence only changes the particle's direction and not its speed, no work is done on the particle by this force:
W = 0.
N.B. The units Joules and Newton-metres are equivalent. [J] ≡ [Nm]
To understand further, try googling 'vector cross product', 'vector dot product'. The magnetic force is a cross product. The definition of work is a dot product. Can you guess why they are called that? :Psee more