Recent content by Steve4Physics

How do you tell the difference between a physicist and a trade-union leader?

Yes, Thanks. I see my mistake in Post #6. I overlooked the (obvious!) fact that the pulley itself has a vertical acceleration of ##A_y##. I don't think your explanation is too hand-wavy! m’s vertical acceleration is the vector sum of: - the vertical acceleration of the pulley (A_y) and -...

In addition to what @TSny has suggested, you could try this... Let ##A_x## and ##A_y## be the horizontal and vertical components of M’s acceleration. (##\frac {A_y}{A_x} = \tan \alpha##). Let ##a_x## and ##a_y## be the horizontal and vertical components of m’s acceleration. ##A_x =a_x ##...

Aagh. Misread the question. Post struck-through.

Of course, relativistic effects need to be accounted.... Edit - please ignore. misread question.

In the connected situation (S1 and S2 joined) condition 1 applies: Torque (S1) = Torque(S2) = 0 If any object - even if it is part of a larger object - has zero angular acceleration (##\alpha##), e.g. if the object is stationary, then the net torque (##\tau##) on the object MUST be zero...

You are comparing two different systems – not two versions of the same system. So your comparison isn’t valid. I'll try to explain why. In the initial system, you have two motors ##M_1## (trying to make rod rotate clockwise (CW)) and ##M_2## (trying to make rod rotate anticlockwise (ACW)). The...

Here in the UK, building insurance often excludes cover for damage caused by infinite forces. For this reason, all our builders and carpenters now receive mandatory physics training in order to reduce the risk of incorrectly positioned PUSH (and PULL) signs.:smile:

A couple of thoughts... No. If a ’subsystem’ had non-zero torque, then it would have some angular acceleration. @anuttarasammyak, you don’t have to worry about infinite forces here! Consider a simple case: a horizontal bar of negligible weight, supported at one end by a hinge and carrying a...

To add to what’s already been said, you are correct but it doesn't matter. If you calculate ##F_y## you will get a negative value. You will then know the actual direction is opposite to the initial ‘guess’. This approach is valuable in complicated systems, where it may not be easy to find all...

It might help to remember that there are two types of equilibrium – translational and rotational. In this question, in the horizontal direction, translational equilibrium requires that ##D \sin(55^\circ) = F##. Part of D’s ‘physical affect’ is to contribute to translational equilibrium. Now...

Pre-retirement I marked physics exam' papers for Edexcel (and for others). Occasionally examination questions are found to be ambiguous/faulty. Similarly for mark schemes. It shouldn’t happen but it does. Any problems are quickly discovered by the markers once the marking starts. Each problem...

It might just be a not-that-great description (notably lacking commas!). The OP wrote: The intended meaning may be this (with block positions A-B-C): "By compressing the spring" [B##\rightarrow##C] "and moving to the equilibrium position" [C##\rightarrow##B] "to the maximum"...

That's OK. But note that the data in the question are supplied to only one significant figure. Technically it would be best if your answer had only one significant figure, though two significant figures would be a reasonable compromise here. (Unless your teacher has advised otherwise.) You...

@aadityav, to clarify your teacher’s intent, you could ask them this: Planet A has a surface gravitational field strength of 51 m/s##^2##. Planet B has a surface gravitational field strength of 61 m/s##^2##. Planet C has a surface gravitational field strength of 71 m/s##^2##. On which...