Physics: Gravity and Weight Concepts
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Questions and Answers

What is the unit of weight as described in the content?

  • Grams (g)
  • Pascals (Pa)
  • Newtons (N) (correct)
  • Kilograms (kg)

    • How does gravitational field strength change in different locations?

  • It increases on the Moon compared to Earth.
  • It is measured in newtons per kilogram (N/kg). (correct)
  • It remains constant regardless of the object's mass.
  • It has no effect on the weight of objects.

    • Why do astronauts appear to be weightless on the International Space Station?

  • They do not have any mass.
  • They are constantly falling towards the Earth. (correct)
  • They are out of the Earth's gravitational field.
  • Gravity is weaker in space than on Earth.

    • What is the gravitational field strength of the Moon?

    <p>1.6 N/kg (A)</p> Signup and view all the answers

    What does an object need to experience weight in a gravitational field?

    <p>To have mass. (C)</p> Signup and view all the answers

    What is the relationship between weight and mass as described?

    <p>Weight and mass are directly proportional. (A)</p> Signup and view all the answers

    Where is the centre of mass of an object typically located?

    <p>At a single point, which can be inside or outside the object. (A)</p> Signup and view all the answers

    How would you calculate the weight of an object with a mass of 100 g on Earth, given that g = 9.8 N/kg?

    <p>Convert mass to kg and use $weight = mass \times g$. (D)</p> Signup and view all the answers

    What happens to the weight of an object if its mass doubles in the same gravitational field strength?

    <p>The weight also doubles. (D)</p> Signup and view all the answers

    What is the unit of measurement for weight as discussed?

    <p>Newtons (N) (D)</p> Signup and view all the answers

    What is the relationship between work done and energy transfer?

    <p>Work done involves energy transfer from one store to another. (B)</p> Signup and view all the answers

    How is the work done by a force calculated?

    <p>Work done is the product of force and distance in the direction of the force. (D)</p> Signup and view all the answers

    What happens to the temperature of an object when work is done against frictional forces?

    <p>The object's temperature increases. (C)</p> Signup and view all the answers

    When calculating work done, which of the following statements is accurate?

    <p>One joule of work is done with a 1 N force moving 1 m. (D)</p> Signup and view all the answers

    Which scenario correctly calculates the work done on an object?

    <p>A rugby team pushed backwards 5 m using a force of 1000 N; work done is 5000 J. (A), A doctor weighed 600 N moved 40 m vertically; work done is 2400 J. (C)</p> Signup and view all the answers

    What visual representation shows all the forces acting on an object?

    <p>Free body diagram (B)</p> Signup and view all the answers

    Which of the following is true about arrows in a free body diagram?

    <p>They should be labeled with force magnitudes. (C)</p> Signup and view all the answers

    What is the primary characteristic of a free body diagram?

    <p>It simplifies a system to focus on forces. (A)</p> Signup and view all the answers

    In a free body diagram, how should the forces be represented?

    <p>As arrows pointing away from the center of the box. (D)</p> Signup and view all the answers

    What is the role of gravity in weight determination?

    <p>It influences the force experienced by an object with mass. (C)</p> Signup and view all the answers

    What components are formed when a single force is resolved into two directions in the context of pulling an object?

    <p>Vertical and horizontal components (A)</p> Signup and view all the answers

    If a child pulls a toy trailer with a force of 5 N at an angle, which of the following correctly represents the resultant horizontal and vertical forces?

    <p>3 N rightwards and 4 N upwards (A)</p> Signup and view all the answers

    How are vector diagrams useful in the context of forces?

    <p>They help in resolving forces into their components (D)</p> Signup and view all the answers

    In a right-angled triangle representing force, what does each side represent?

    <p>The magnitude of the forces acting in different directions (A)</p> Signup and view all the answers

    Which scale could be appropriately used for drawing forces in a vector diagram for clarity?

    <p>1 cm = 1 N (A)</p> Signup and view all the answers

    Flashcards

    Gravity

    The force of attraction between any two objects with mass.

    Mass

    The amount of matter an object contains. Mass is measured in kilograms (kg) or grams (g).

    Weight

    The force acting on an object due to gravity. It has the unit newtons (N) and acts towards the center of a gravitational field.

    Gravitational Field Strength

    The strength of gravity at a specific location. It is measured in newtons per kilogram (N/kg).

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    Non-contact force

    A push or pull acting between objects that are not physically touching when they interact.

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    What is weight?

    The force acting on an object due to the pull of gravity from a massive object like a planet. The force acts towards the centre of the planet and is measured in newtons (N).

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    What is the centre of mass?

    The point representing the mean position of the matter in a body.

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    What is the relationship between weight and mass?

    The weight of an object is directly proportional to its mass. This means that for a given gravitational field strength, the greater the mass of the object, the greater its weight.

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    How do you calculate an object's weight?

    An apple has a mass of 100 g. To calculate its weight on Earth, we use the equation: Weight = mass x gravitational acceleration.

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    Where is an object's centre of mass?

    Depending on the object's shape, its centre of mass can be inside or outside it.

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    What is work?

    The transfer of energy from one store to another. Work done = force × distance moved in the direction of the force.

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    What is work done?

    The amount of energy it takes to do a task. Measured in joules (J).

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    How can work affect temperature?

    When work is done against frictional forces acting on an object, the object's temperature increases.

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    How do you calculate work done?

    If you know the force and distance moved, you can calculate the work done using this equation: work done = force × distance.

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    Free body diagram

    A simplified drawing of an object or system showing the forces acting on it. Forces are shown as arrows pointing away from the center of a box or dot representing the object.

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    Relationship between weight and mass

    The force of gravity acting on an object is directly proportional to its mass. This means that for a given gravitational field strength, the greater the mass of the object, the greater its weight.

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    Representing an object in a free body diagram

    Free body diagrams help visualize the forces acting on an object. Objects are represented as boxes or dots, and forces are depicted as arrows pointing away from the center.

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    What is gravity?

    The force of attraction between any two objects with mass. The more massive the objects are, the stronger the gravitational force between them.

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    What is a component force?

    A force that acts on an object and can be broken down into two component forces acting at right angles to each other.

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    What is a vector diagram?

    A diagram that shows the forces acting on an object as arrows.

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    What is resolving a force?

    The process of separating a single force into two forces acting perpendicular to each other.

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    What is resultant force?

    The total force that is the result of adding two or more forces together.

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    Study Notes

    Gravity and Weight

    • Gravity is a fundamental force affecting objects with mass in a gravitational field.
    • Weight is the force an object experiences due to gravity acting toward the center of the attracting body.
    • All objects with mass create a gravitational field.
    • The greater the mass, the stronger the gravitational field.
    • Weight is measured in Newtons (N).
    • Weight is a non-contact force.
    • Weight can be measured using a spring balance (Newton meter).
    • Gravitational field strength (g) is measured in Newtons per kilogram (N/kg).
    • Earth's gravitational field strength is 9.8 N/kg.
    • An object's weight is directly proportional to its mass.
    • This means an object with 1 kg of mass experiences a force of 9.8 N on Earth.
    • The Moon's gravitational field strength is 1.6 N/kg.
    • An astronaut weighs less on the Moon than on Earth due to the weaker gravitational field.
    • Astronauts in the International Space Station appear weightless.
    • They are still within Earth's gravitational field and experience weight.
    • Their apparent weightlessness is due to continuous freefall around the Earth.
    • An object's weight is determined by its mass and the gravitational field strength.
    • The centre of mass is the point representing the average position of matter in an object; this point can lie inside or outside the object depending on its shape.
    • A free body diagram simplifies an object by representing it as a box or a dot, showing the forces acting on it as arrows.
    • Forces are represented by arrows, which are labelled to show magnitude and type.
    • Free body diagrams aren't drawn to scale, though it's sometimes helpful to do so.
    • An apple with a mass of 100 g would weigh 0.98 N on Earth (100 g = 0.1 kg, 0.1 kg * 9.8 N/kg = 0.98 N).
    • Work is done when energy is transferred from one store to another.
    • Work is also done when a force causes an object to move.
    • Work done = force × distance moved in the direction of the force (measured in joules (J) or newton-metres (Nm)).
    • One joule of work is done when a force of 1 N causes a movement of 1 m.
    • Work done against friction increases an object's temperature.
    • A doctor weighing 600 N moved 40 m by a lift would have 24,000 J of work done on them.
    • A rugby team applying 1000 N of force to push the other team 5 m would have done 5000 J of work.

    Component Forces

    • Two or more forces can be combined to find a resultant force.
    • A single force can be broken down into component forces at right angles to each other.
    • For example, a 5 N pulling force on a toy trailer can be split into a horizontal component pulling it to the right and a vertical component pulling it upwards.
    • Vector diagrams (right-angled triangles) are often used to show component forces.
    • A scale can be used on a diagram (e.g., 1 cm = 1 N).
    • Measure the lengths of the horizontal and vertical lines in the diagram.
    • Use the scale to convert the measured lengths to corresponding forces.
    • For example, a 5 N pulling force might resolve into a 4 N force to the right and a 3 N force upwards.
    • The component forces have the same effect as the original force.

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    Description

    Explore the fundamental concepts of gravity and weight in this quiz. Learn how gravitational fields are created by mass and how weight is measured in different environments, including the Earth and the Moon. Understand the distinction between weight and apparent weightlessness experienced by astronauts.

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