Recent content by TomK

Thank you for the response. This answers my question. I think my misconception came from thinking that the object (more dense than water) would have to be sufficiently heavy to displace more water when thrown overboard. However, my working shows that, under the assumed circumstances, m could...

I was asked this question: Assume you're sitting in a boat (you and the boat, together, are a mass M) which also contains a heavy object (of mass m). The boat (inc. you and the heavy object) is floating in a pond (a fixed body of water, rather than open sea). If you throw the object overboard...

Interesting. Is there a link to show/describe this experiment?

Thank you for answering my questions. I will look more into 'force due to pressure by integration'. I'm not at university yet, so I haven't had to use integration in real-world problems, but it could be useful to learn in-advance.

Is the horizontal component of the area the same as taking a horizontal cross-section of the shape up to where the fluid line reaches? For example, if you put in a cone with a circular base into fluid (tip-first - i.e. with the tip facing downwards), would the horizontal area be the same as...

I think I understand now. As long as there is fluid in-contact with the base surface of the object, there will be an upthrust. Does this upthrust always equal the weight of fluid which the object displaced, regardless of what percentage of the object is submerged? I'm assuming that a base...

I had some questions about Archimedes' Principle. This image shows an object being gradually submerged into fluid: As far as I'm aware, when the object is floating, weight of fluid displaced by object = upthrust acting upwards on the object. When the object is fully submerged, volume of the...

That makes more sense now. Thank you.

That's it. I confused θ with pi at the very beginning. Thank you.

Why do we use the initial velocities of zero when you could use the velocity immediately before the collision (i.e. X has velocity v)? How do you know which to use? I understand the momentum calculation, but I don't understand why you don't use the velocities right before the collision.

I don't understand why. You have the angle θ/2 in the bottom-right corner (between ramp and string). The 90 degree angle is at the top corner. The triangle appears to also be isoceles. If you use the angle by the string, you get x2 to be the opposite side and the ramp to be the hypotenuse...

I don't understand the reasoning of this question's answer. The answer is velocity = 0 (option A). A while ago, I was told that, since the magnets were held at-rest (before being let go), they must have no velocity after the collision. What about the velocity which they had just before the...

I can't see where I've made a mistake. I just used: moment = force x perpendicular distance (from hinge to direction of force)If you make a triangle connecting hinge and force going down from centre of ramp: sin(θ) = O/H sin(θ) = x1/(l/2) x1 = lsin(θ)/2 CW moment = Wlsin(θ)/2If you make a...

I did this question a while ago, but I wanted to ask how you know that the maximum tension occurs when θ = 90 degrees. I worked out the moments, and I got: tension = Wcos(θ/2) I'm thinking that I did it wrong. We want cos(θ/2) to be as large as possible to maximise tension. Of course, θ...

Thank you. I now know I should have given F a '-' sign in-front, since force is acting in the negative direction, as I assumed positive to be right to left. initial velocity = +u final velocity = -v F = change in p/change in t -F = (-mv - mu)/(t2 - t1) -F(t2 - t1) = -mv - mu mv = F(t2 - t1)...