Recent content by IsakVern

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    I Why is 2.5 times the radius the minimum height needed to do a loop?

    I realize that, but I'm wondering whether there's a reason why there is a factor of 5/2, as opposed to any other number. Is there anything special about 5/2?
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    I Why is 2.5 times the radius the minimum height needed to do a loop?

    The height can be determined by conservation of energy (ignoring all friction). The mechanical energy when the car is at rest, equals the mechanical energy when the car is in the middle of the loop (at the top of the loop): \begin{equation} E_{0} = E_{loop} \\ mgh_0 = \frac{1}{2}mv^2+mgh_{loop}...
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    I Stopping Scooters: Comparing KE & AM

    So if the scooter is coming towards a person standing still, the person must apply the same force on either scooter in order to stop it, correct? So does the difference in angular momentum only affect the scooter's ability to stay upright?
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    Exploring the Logical/Geometrical Explanation of Escape Velocity

    If you derive the equation for orbital velocity you get \begin{equation} v_{orbit} = \sqrt{\frac{GM}{R}} \end{equation} and for escape velocity you get \begin{equation} v_{escape} = \sqrt{\frac{2GM}{R}}=\sqrt{2}\,v_{orbit} \end{equation} I'm wondering if there is a logical/geometrical...
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    I Stopping Scooters: Comparing KE & AM

    Assume that a kick-scooter rolls on a smooth surface without slipping, and that - for simplicity - all the mass of the scooter's two wheels are distributed like a loop/ring, i.e. around the edges of the wheels with no mass in the centre of the wheels. The wheels have radius R and the scooter is...
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    I Velocity Addition & Relativity of Simultaneity

    I have some issues understanding the following thought experiment: Suppose you are standing still, and two balls are moving towards you from opposite direction. From your own reference frame, Ball A is ##10^5## m away from you, moving towards you from the left with speed ##0.8c##, and Ball B is...
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    I Energy needed to launch a spaceship into Space

    The assumed state of the spaceship is that it has zero velocity when it reaches 100 km.
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    I Energy needed to launch a spaceship into Space

    A given planet has a mass, M = 6.42*10^23 kg, and radius, R = 3.39 * 10^6 m. The gravitational konstant is G = 6.67*10^-11 A spaceship with mass m = 4000 kg is launched from the planets surface. How much energy is needed to send the spaceship to a height h = 100 km above the planets surface?
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