Physics Work and Energy Quiz
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Questions and Answers

What is the formula for calculating work when force and displacement are in the same direction?

  • W = F * S * cos 90°
  • W = - F * S
  • W = F * S (correct)
  • W = F * S * cos θ

    • Negative work occurs when the force and displacement are moving in the same direction.

    False

    What is the value of work done when a force of 15N moves an object a distance of 5m in the direction of the force?

    75 J

    If the force is perpendicular to the displacement, then the work done is ______.

    <p>0</p> Signup and view all the answers

    Match the type of work to its condition:

    <p>Positive Work = 0° ≤ θ &lt; 90° Negative Work = 90° &lt; θ ≤ 180° Zero Work = θ = 90° or Displacement is 0</p> Signup and view all the answers

    What is the formula for calculating kinetic energy?

    <p>$KE = rac{1}{2} mv^2$</p> Signup and view all the answers

    Kinetic energy is a vector quantity.

    <p>False</p> Signup and view all the answers

    What happens to an object's kinetic energy when it accelerates?

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

    The energy possessed by an object due to its motion is called ______.

    <p>kinetic energy</p> Signup and view all the answers

    What is the work done by the porter lifting the suitcase?

    <p>392 J</p> Signup and view all the answers

    Energy is measured in Joules.

    <p>True</p> Signup and view all the answers

    Match the following variables with their meanings in the kinetic energy formula:

    <p>KE = Kinetic energy of the object m = Mass of the object v = Velocity of the object 1/2 = A constant factor in kinetic energy calculation</p> Signup and view all the answers

    What is the gravitational force acting on the suitcase lifted by the porter?

    <p>196 N</p> Signup and view all the answers

    What is the formula to calculate work when force and displacement are at an angle?

    <p>$W = F imes S imes cos heta$</p> Signup and view all the answers

    Work is done when a force is applied but there is no displacement of the object.

    <p>False</p> Signup and view all the answers

    When a spring is compressed or stretched, the work done by the spring is ___ when the spring is compressed.

    <p>negative</p> Signup and view all the answers

    Match the following terms with their definitions:

    <p>Work = Force applied over a distance Gravitational Force = Attraction between masses Spring Force = Force by a compressed or stretched spring Energy = Ability to do work</p> Signup and view all the answers

    What is the unit of work in the International System of Units (S.I.)?

    <p>Joule</p> Signup and view all the answers

    The value of gravitational acceleration (g) is approximately _____ m/s².

    <p>9.8</p> Signup and view all the answers

    Match the following angles with their corresponding cosine values:

    <p>0° = 1 90° = 0 180° = -1 45° = 0.707</p> Signup and view all the answers

    What is the initial kinetic energy of a body of mass 10 kg moving at a velocity of 5 m/s?

    <p>125 Joules</p> Signup and view all the answers

    Doubling the velocity results in quadrupling the kinetic energy.

    <p>True</p> Signup and view all the answers

    What is the mass of the body in the problem?

    <p>10 kg</p> Signup and view all the answers

    The final kinetic energy when the velocity is doubled to 10 m/s is ___ Joules.

    <p>500</p> Signup and view all the answers

    Match the following velocities with their respective kinetic energies:

    <p>5 m/s = 125 Joules 10 m/s = 500 Joules</p> Signup and view all the answers

    Increasing the mass of an object has no effect on its kinetic energy if the velocity remains constant.

    <p>False</p> Signup and view all the answers

    What is the effect of a decrease in velocity on the kinetic energy of an object?

    <p>The kinetic energy decreases.</p> Signup and view all the answers

    The work done on an object can be calculated as the change in _____.

    <p>energy</p> Signup and view all the answers

    Match the following problems with their corresponding calculations:

    <p>Bullet problem = Calculating kinetic energy from bullet velocity Car problem = Calculating work done during braking Truck problem = Comparing kinetic energy between truck speeds Force and mass = Determining braking forces based on mass</p> Signup and view all the answers

    What is the SI unit of power?

    <p>Watt</p> Signup and view all the answers

    Kinetic Energy (KE) transforms into Potential Energy (PE) when an object is thrown upwards.

    <p>True</p> Signup and view all the answers

    What is the formula for power?

    <p>P = W/t or P = E/t</p> Signup and view all the answers

    1 Watt is equal to ______ Joule of work done in 1 second.

    <p>1</p> Signup and view all the answers

    Match the following energy transformations with their descriptions:

    <p>Light = Electric --&gt; Solar cell/panel Sound = Electric --&gt; Microphone Electric = Sound --&gt; Speaker Kinetic Energy = Potential Energy when thrown upwards</p> Signup and view all the answers

    What is the work required to bring the bullet to rest with a mass of 0.05 kg and an initial velocity of 200 m/s?

    <p>1000 J</p> Signup and view all the answers

    Gravitational potential energy is the energy an object has due to its speed.

    <p>False</p> Signup and view all the answers

    What is the formula for potential energy?

    <p>U = mgh</p> Signup and view all the answers

    The work done by the brakes on a truck with a mass of 2000 kg, initially traveling at 15 m/s and slowing down to 5 m/s, is _____ J.

    <p>200000</p> Signup and view all the answers

    What is the potential energy of an object with a mass of 5 kg raised to a height of 3 meters? (Use $g = 9.81 rac{m}{s^2}$)

    <p>147.15 J</p> Signup and view all the answers

    What does the equation E = mgh represent?

    <p>Gravitational potential energy</p> Signup and view all the answers

    The potential energy of an object depends on the path taken to reach its height.

    <p>False</p> Signup and view all the answers

    The final calculated power value from the given calculations is 3820W.

    <p>True</p> Signup and view all the answers

    What are the two forms of energy produced when a fuel undergoes combustion?

    <p>Light and Heat</p> Signup and view all the answers

    What is the result of the calculation when using the values 200 kg, 9.8 m/s², and a height of 10 m in the formula for gravitational potential energy?

    <p>-19600 J</p> Signup and view all the answers

    The law of conservation of energy states that mass can neither be ______ nor destroyed.

    <p>created</p> Signup and view all the answers

    In the equation P = E/t, the variable 't' represents _____ time.

    <p>time</p> Signup and view all the answers

    Match the following energy conversions with their processes:

    <p>Photosynthesis = Light → Chemical Burning of fuel = Chemical → Heat Electric heater = Electric → Heat Incandescent bulb = Electric → Light</p> Signup and view all the answers

    Match the following parameters with their definitions:

    <p>E = Energy measured in Joules P = Power measured in Watts m = Mass measured in kilograms g = Acceleration due to gravity, approx. 9.8 m/s²</p> Signup and view all the answers

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