Recent content by Hemingway

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    Mirror equations - basic math error - what is it?

    Thank you! It's hard sometimes when you instinctively know you're doing the wrong thing - but you've just hit an intellectual wall. Thank you so much everybody for helping me out. Many thanks CollinsMark - that would have taken some time to do and I appreciate it.
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    Mirror equations - basic math error - what is it?

    1/do - 1/.25do = 1/-14 1/.75do = 1/-14 1.3do = 1/-14 ... This still doesn't seem to get to the answer. Could someone show me step by step to how they would get to the answer? I am just too confused. I tried :) I'm finding it difficult to simplify with the inverse. Cheers
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    Mirror equations - basic math error - what is it?

    Homework Statement An object is located 14.0cm in front of a convex mirror the image is being 7.00cm behind the mirror. A second object twice as tall as the first one is placed in front of the mirror, but at a different location. The image of this second object had the same height as the other...
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    What is the explanation for using sin 30 in 2D kinematics?

    That was exactly what I was after - thank you very, very much :)
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    What is the explanation for using sin 30 in 2D kinematics?

    Homework Statement A tennis ball is thrown from ground level with velocity vo directed sin 30 above the horizontal. If it takes the ball 1.0s to reach the top of its trajectory, what is the magnitude of the initial velocity? Homework Equations The initial vertical component of...
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    Conservation of Mechanical Energy - I can't see what I'm doing wrong

    oh my gosh. I must have been in a haze of stupidity. I can't believe I couldn't do this. Fresh eyes makes a difference. Thanks to those hanging in there. Oh my - how embarrassing.
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    Conservation of Mechanical Energy - I can't see what I'm doing wrong

    basically I cannot see why 2g would not cancel ... and if I knew what I needed I'd recognise how absurd that statement is - but if someone could condescend to show me how step by step I'd be so, so appreciative. Sorry, just having one of those self-confidence draining moments :)
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    Conservation of Mechanical Energy - I can't see what I'm doing wrong

    Thanks so much for your reply. As I said above, I am drawing an algebraic blank from how one gets from the first equation in my first post, to the second equation which is: v2 = u2+2g (h0-hf) I know it's elementary, but I know how we get to v2 +2ghf =u2+ 2gh0 but not to v2 = u2+2g (h0-hf)...
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    Conservation of Mechanical Energy - I can't see what I'm doing wrong

    okay I worked out how we get to... v2 + 2ghf = u2 +2gh0 v2 = u2 + 2gh0 - 2ghf Can anyone show me why +2gh doesn't cancel by showing me what does happen step by step? Alternatively can someone give me a url website/video that I can look at that will show me the princples as to how this...
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    Conservation of Mechanical Energy - I can't see what I'm doing wrong

    Oh yes, that was never in dispute - I believe I prefaced the problem with that statement. I'll take a look. Thanks for the insight tsw99 :)
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    Conservation of Mechanical Energy - I can't see what I'm doing wrong

    Okay. Thank you for showing me that. I still don't understand why that is the case... I don't want you to waste your time showing me as you've already taken the time :) but is there a url I can look at to see why the '1/2's don't cancel but instead = 2 ?? I'm just a bit stuck I'm afraid :)
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    Conservation of Mechanical Energy - I can't see what I'm doing wrong

    I suppose I need the working from equation (1) to it's manipulation to be equation (2) - as I just don't conceptually understand how the g's don't cancel if the mass cancels...
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    Conservation of Mechanical Energy - I can't see what I'm doing wrong

    I'm not exactly sure with what you mean. How would I get a factor of 2? Perhaps there should be a factor of 2 but how do I get that? Once again, I am not sure how there is '2g' in the second equation... :/
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    Conservation of Mechanical Energy - I can't see what I'm doing wrong

    Homework Statement A motorcyclist is trying to leap across a canyon. The first cliff is 70m high, she wants to jump to the cliff 35m high. She is traveling 38m/s. Ignoring air resistance, find the speed with which the cycle strikes the ground on the other side. I think (and am very worried...
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    Collisions problem completed - is it correct?

    Thank you very much - I appreciate it.
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