Recent content by Steve4Physics

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...

I guess you meant to say something like "if the cylinder's initial angular speed = 0 and it then rolls without slipping". Not quite right. For rolling-without slipping (RWS), the direction of the frictional force is always uphill. (You might want to think about why this is so!) So for RWS...

If still in doubt maybe this will help... Consider a mixture of two materials. The amounts of each are ##A## and ##B##. Total ##T = A+B##. Suppose ##A## is fixed but ##B## (and hence ##T##) can be changed. Let ##P_B## % be the percentage of B present. I.e. ##P_B = \frac BT \times 100##...

On a point of terminology, the problem+answer is not a true paradox. It is an example of a veridical paradox. That is one which appears to be paradoxical but on analysis is not - so there is no true paradox.

The coefficient of kinetic friction is generally a bit smaller than the static coefficient. Of course, the laws of physics may vary slightly in NC. Really? They can't use a metre-rule or a tape measure???! Give them a short measurement exercise. You can make it ‘fun’. E.g. they individually...

From what you have said, it sounds like the students are working at an introductory level. You might need to improvise a bit but here are a few simple experiments... 1. Find an object’s unknown mass using a ‘see-saw’ balance (e.g. a metre rule resting on pivot). This requires known masses and...

For an essentially geometric proof (no standard trig' identities used) see this 3 minute (appox.) video.

The solution below is not mine – I saw it on YouTube, here. This is just my summary. 1. Add 3 squares and consider the triangle containing angle B: 2. Add 2 (reflected) copies of the triangle: 3. Note, below, that triangle PQR (red) is right-angled (at P) and isosceles, so has angles...

With the diffraction grating ('grid') like this: - to which axis of rotation (x, y or z) do you think part a) refers ? - to which axis of rotation (x, y or z) do you think part b) refers ? What is 'iz'? 'd' is the distance between adjacent lines in the 'grid'. It can't change. I recommend...

SHM requires that the restoring force is proportional to the displacement from the equilibrium position. Find the limit of proportionality (sometimes called the proportional limit) for steel. The maximum amplitude for SHM corresponds to the steel stretched to to this limit.