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Physics Final Exam Study Guide

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  • Define momentum

    Momentum depends on mass and velocity and is given by \(p=mv\).

  • What is impulse?

    Impulse is the force applied over a time interval, expressed as \(J=F\Delta t\).

  • How does impulse change momentum?

    Impulse changes momentum according to \(J=\Delta p\).

  • Two ways to increase impulse

    Increase the force applied or increase the time interval over which the force is applied.

  • Why does follow-through increase impulse?

    Follow-through increases the contact time, which increases impulse and thus changes momentum more effectively.

  • Why does increasing contact time reduce force?

    Increasing contact time spreads the force over a longer period, reducing the peak force experienced.

  • What is conserved in all collisions?

    Total momentum is conserved in all collisions.

  • Difference between elastic and inelastic collisions

    Elastic collisions conserve both momentum and kinetic energy; inelastic collisions conserve momentum but not kinetic energy.

  • What is a perfectly inelastic collision?

    A collision where objects stick together after impact.

  • Collision momentum conservation equation

    \(m_1v_{1i} + m_2v_{2i} = m_1v_{1f} + m_2v_{2f}\)

  • Work formula

    Work is force times distance: \(W=Fd\).

  • Potential energy formula

    Potential energy is given by \(PE=mgh\).

  • Kinetic energy formula

    Kinetic energy is \(KE=\frac{1}{2}mv^2\).

  • Power formula

    Power is work done over time: \(P=\frac{W}{t}\).

  • How does kinetic energy change when speed triples?

    Kinetic energy increases by the square of the speed increase, so it becomes 9 times greater.

  • Newton’s Law of Gravitation formula

    \(F=G\frac{m_1m_2}{r^2}\)

  • Effect on gravity when distance doubles

    Gravity force becomes one-fourth as strong when distance doubles.

  • Effect on gravity when both masses double

    Gravity force quadruples when both masses double.

  • Why are astronauts weightless in orbit?

    They are in free fall, continuously falling around Earth, creating a sensation of weightlessness.

  • Time dilation formula

    \(t' = \frac{t}{\sqrt{1 - \frac{v^2}{c^2}}}\)

  • Why do moving clocks run slower?

    Because of time dilation, moving clocks run slower relative to stationary observers.

  • Length contraction formula

    \(L' = L\sqrt{1 - \frac{v^2}{c^2}}\)

  • What happens to length at high speeds?

    Objects contract in length along the direction of motion.

  • Mass-energy equivalence formula

    \(E=mc^2\)

  • Explain gravity as curved spacetime

    Mass bends spacetime, causing objects to follow curved paths, which we perceive as gravity.

  • Why does time run slower near massive objects?

    Stronger gravity causes time to slow down due to spacetime curvature.

  • What happens to surface gravity if radius shrinks to 1/3?

    Surface gravity increases because gravity is inversely proportional to the square of the radius.