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Physics: Newtonian Mechanics and Forces

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이 집합의 용어 (21)

  • What is inertia?

    Inertia is a property of matter describing an object's resistance to changes in its state of motion; it is not a force.

  • Who first introduced the concept of inertia?

    Galileo introduced the concept of inertia before Newton formalized it.

  • What does Newton's First Law of Motion state about motion and forces?

    An object moving at constant velocity or at rest will remain so unless acted on by an unbalanced force.

  • Why do you lurch to the right when a bus turns left?

    Your body's inertia keeps it moving straight forward while the bus turns beneath you; no real outward force pushes you.

  • Is there a real outward force pushing you when a vehicle turns?

    No; the apparent outward force is due to inertia in a non-inertial reference frame.

  • What is mechanical equilibrium?

    Mechanical equilibrium occurs when the net force on an object is zero, resulting in zero acceleration.

  • Can an object moving at constant velocity be in mechanical equilibrium?

    Yes; zero net force means zero acceleration, not necessarily zero velocity.

  • What is tension in ropes or wires?

    Tension is a pulling force along a rope or wire that tends to stretch it.

  • How does the angle of ropes affect tension when supporting a weight?

    More horizontal ropes require greater tension to provide the same vertical support.

  • What happens to a coin tossed straight up inside an accelerating train?

    The coin keeps its original horizontal velocity, so it lands behind you as the train moves forward.

  • What if the train moves at constant velocity when you toss the coin up?

    The coin lands back in your hand because you and the coin share the same horizontal velocity.

  • What is the difference between vector and scalar quantities?

    Vectors have magnitude and direction; scalars have magnitude only.

  • Why must force be treated as a vector quantity?

    Because direction affects how forces combine and cancel out.

  • What is the net force on an object falling at constant (terminal) velocity?

    The net force is zero because gravity and air resistance balance exactly.

  • Does zero net force mean no forces are acting?

    No; it means all forces cancel out, but multiple forces can still be present.

  • What path does an object follow when no net force acts on it?

    A straight line at constant speed.

  • Why does a ball on a string travel in a circle rather than a straight line?

    The string provides a centripetal force pulling the ball toward the center, causing circular motion.

  • How does rope tension change as the angle from vertical increases?

    Tension increases because only the vertical component supports the load; more horizontal means greater tension.

  • If two ropes support a sign symmetrically at 45° from vertical, how does tension compare to half the sign's weight?

    Each rope's tension is more than half the sign's weight due to the angle reducing vertical components.

  • What is the sum of tensions in ropes supporting a scaffold weighing 1000 N in equilibrium?

    The total tension equals 1000 N, matching the scaffold's weight.

  • If one painter is heavier on a scaffold, are the rope tensions equal?

    No; the rope under the heavier side has greater tension, but tensions sum to total weight.