Newtons Law Part 2
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Questions and Answers

What is the primary effect of a deeper counter jump on vertical jumping performance?

  • It decreases the overall energy output required for jumping.
  • It leads to a decrease in the time spent in the air.
  • It increases the force exerted on the ground immediately.
  • It increases the contact time with the ground, enhancing momentum. (correct)

    • How does longer landing time through a deep squat contribute to injury prevention?

  • It distributes the force evenly across the lower body.
  • It minimizes the total distance to reach the ground.
  • It allows for a quicker recovery time after landing.
  • It applies a smaller force over a longer period of time. (correct)

    • What is the result of performing isometric muscle contractions in terms of mechanical work?

  • Zero work is performed. (correct)
  • Variable work depending on muscle mass.
  • Positive work is performed.
  • Negative work is performed.

    • Which phase of the pitch process converts potential energy into kinetic energy?

    <p>Cocking phase.</p> Signup and view all the answers

    What is the effect of force and displacement being in opposite directions on work performed?

    <p>It results in negative work performed.</p> Signup and view all the answers

    How does a gymnast maximize their kinetic energy during a vault?

    <p>By running as fast as possible during their approach.</p> Signup and view all the answers

    What role does elastic energy play in a gymnast's vault after foot planting on the springboard?

    <p>It is stored temporarily until the board is released.</p> Signup and view all the answers

    What happens during the acceleration phase of a pitch as the pitcher prepares to throw?

    <p>The kinetic energy is at its peak.</p> Signup and view all the answers

    What is the formula for the force of friction based on the coefficient of friction and normal force?

    <p>$F_{friction} = μ * F_{normal}$</p> Signup and view all the answers

    Which condition leads to the box beginning to slip when pushed?

    <p>$F_{push} &gt; F_{friction}$</p> Signup and view all the answers

    What does the symbol Σ generally represent in equations of motion?

    <p>The total or net force in a given direction</p> Signup and view all the answers

    When analyzing forces acting on a stationary box, which statement is correct?

    <p>Normal force is equal to the gravitational force acting on the box.</p> Signup and view all the answers

    If the coefficient of friction (μ) is increased, what effect does it have on the force of friction?

    <p>The force of friction increases proportionally.</p> Signup and view all the answers

    What is the relationship between normal force (FNormal) and gravitational force (Fg) for an object at rest on a horizontal surface?

    <p>FNormal = Fg</p> Signup and view all the answers

    Which of the following statements about tipping and slipping is true?

    <p>Tipping occurs when the center of mass shifts too far outside the base.</p> Signup and view all the answers

    How can one calculate the normal force acting on an object resting on a scale at an angle?

    <p>FNormal = Fg * cos(θ)</p> Signup and view all the answers

    What is the result when positive work is done on an object?

    <p>The object's energy increases.</p> Signup and view all the answers

    How is power defined in the context of work and energy?

    <p>The work done divided by the time taken.</p> Signup and view all the answers

    If a 0.2 kg baseball is stopped over a distance of 0.125 m from a speed of 22 m/s, what is the nature of work done on the baseball?

    <p>The work is negative, decreasing the kinetic energy.</p> Signup and view all the answers

    What happens to a diver's potential energy when they drop from 10 m to 5 m above the water?

    <p>It decreases.</p> Signup and view all the answers

    In the formula for power, which variables are essential for its calculation when moving an object at a constant velocity?

    <p>Force and velocity.</p> Signup and view all the answers

    What is the likely consequence of friction acting on a moving box on a sticky floor?

    <p>Work is negative, decreasing kinetic energy.</p> Signup and view all the answers

    If a gymnast applies a force to vault, how does this relate to energy transfer?

    <p>The energy is transferred from the ground to the gymnast.</p> Signup and view all the answers

    How does the physics of energy transfer apply to a pitcher throwing a baseball?

    <p>Work is done through acceleration of the arm.</p> Signup and view all the answers

    How does the ability to exert more power affect the speed of lifting weights?

    <p>More power enables weights to be lifted quickly.</p> Signup and view all the answers

    Which factor contributes to a box being more stable and harder to tip over?

    <p>Adding weight to the box.</p> Signup and view all the answers

    What effect does following through on a golf drive have on the ball's momentum?

    <p>It extends the time the force is applied, increasing impulse.</p> Signup and view all the answers

    How does a soft landing technique affect the forces experienced during a landing?

    <p>It dissipates force over a longer time, resulting in lower impact force.</p> Signup and view all the answers

    What is the relationship between the coefficient of friction and the likelihood of an object sliding?

    <p>Pushing harder than the frictional force causes sliding.</p> Signup and view all the answers

    What is the calculated force experienced by a 50 kg gymnast landing hard over 0.20 seconds?

    <p>937.5 N</p> Signup and view all the answers

    If a person has reduced power, how might this impact their ability to cross the street?

    <p>They may need more time to cross due to slower movements.</p> Signup and view all the answers

    Which condition leads to tipping of an object rather than sliding?

    <p>Pushing high up when the base is wide.</p> Signup and view all the answers

    What is the primary goal of force composition?

    <p>To determine the net effect of combined forces.</p> Signup and view all the answers

    Which method uses a tip-to-tail approach for combining non-parallel forces?

    <p>Polygon Method</p> Signup and view all the answers

    If a force is resolved into components, which of the following represents the stated method?

    <p>Replacing a force with its components while maintaining the total effect.</p> Signup and view all the answers

    When drawing a free body diagram, which of the following steps does NOT belong?

    <p>Measure the acceleration of the body.</p> Signup and view all the answers

    What is the significance of the moment arm when considering forces?

    <p>It impacts the torque produced by the force.</p> Signup and view all the answers

    Which of the following describes the X and Y components of a force?

    <p>One can be zero while the other is not.</p> Signup and view all the answers

    In the context of free body diagrams, what does the statement Σ = 0 imply?

    <p>The object is in static equilibrium.</p> Signup and view all the answers

    If a ballerina's lower leg has a weight of 30 N and a moment arm of 0.50 m, what is the importance of this moment arm for her movements?

    <p>It affects the effectiveness of the leg's propulsion.</p> Signup and view all the answers

    What is the potential energy of a 60kg diver at a height of 5m above the water?

    <p>2940 J</p> Signup and view all the answers

    When the diver enters the water at 0m, what is the kinetic energy just before entry?

    <p>5880 J</p> Signup and view all the answers

    What is the average force required to stop a 0.2 kg baseball moving at 22 m/s over a distance of 0.25 m?

    <p>193.6 N</p> Signup and view all the answers

    What is the work performed on the diver if the water slows him down by 50% upon entry?

    <p>4410 J</p> Signup and view all the answers

    How much kinetic energy does the baseball have before being stopped by the player?

    <p>48.4 J</p> Signup and view all the answers

    What is the relation between power and work when lifting a 100 kg weight to a height of 2 m in 5 seconds?

    <p>Power is calculated as total work divided by time.</p> Signup and view all the answers

    What would be the average force required to stop the same baseball over a distance of 0.125 m?

    <p>387.2 N</p> Signup and view all the answers

    How does the recoil phase in the muscle-tendon unit affect the throwing motion?

    <p>It stores energy to be released during the throw.</p> Signup and view all the answers

    Study Notes

    Newton's Laws

    • Newton's laws describe how forces act on objects
    • Combining two or more forces determines the net effect.
    • Linear forces are added (if in line) or subtracted (if opposite direction)

    Composition and Resolution of Forces

    • Composition is combining two or more forces to find the net effect
    • Resolution is replacing a single force with two or more. components
      • Usually resolved into vertical (Fy) and horizontal (Fx) components
      • For any force (F)
        • X-component (Fx)
        • Y-component (Fy) -Sometimes one of these (Fx or Fy) may be zero

    Free Body Diagrams

    • Steps to draw a Free Body Diagram:
      1. Identify and isolate the free body.
      2. Establish a coordinate reference frame.
      3. Draw all forces (internal and external) on the body.
      4. Draw the joint reaction force.
      5. Write the governing equations of motion (ΣFx = 0; ΣFy = 0; Σ = 0)).

    Tipping vs. Slipping

    • Friction: A force that opposes motion between surfaces
      • Coefficient of friction (μ) describes how "sticky" a surface is
      • Friction force = μ * Normal Force
    • Box tipping
      • If push force is greater than friction, the object will begin to slide
      • If push force is greater than the torque created by gravity, the object will begin to tip

    Impulse-Momentum

    • Momentum (M): The quantity of motion possessed by an object
    • M = m * v (mass x velocity).
    • Impulse: The quantity of net force applied over a period of time Impulse = ΣF * t 
    • The impulse applied to an object is equal to the change in momentum.
    • Impulse–momentum relationship  ΣF * t = Δmv

    Work, Energy, Power

    • Work: The product of force and the displacement in the direction of the force.
      • Work = Force * distance
    • Energy: The capacity to do work.
    • Kinetic Energy: Energy of motion (KE = 1/2mv²)
    • Potential Energy: Energy due to position (PE = mgh)
    • Elastic Energy: Energy due to deformation (EE = 1/2kx²)
    • Power: The rate at which work is done or energy is transferred.
      • Power = Work / time

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    Newtons Laws Session 2 POST - Part 2 PDF

    Description

    This quiz covers Newton's Laws of motion and the principles of composition and resolution of forces. Learn about free body diagrams, how to isolate forces, and the concepts of tipping versus slipping. Test your understanding of these fundamental physics concepts.

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