1 FORCES AND MOTION

    Cards (50)

    • How is speed defined?
      Speed is defined as the distance travelled per unit time.
    • What does it mean if the speed of something is changing?
      If the speed is changing, it is accelerating or decelerating.
    • What is the acceleration of free fall near to the Earth?
      The acceleration of free fall near to the Earth is constant.
    • What is the formula for average speed?
      average speed=\text{average speed} =total distancetotal time \frac{\text{total distance}}{\text{total time}}
    • How is velocity defined?
      Velocity is the speed in a given direction.
    • What is acceleration?
      Acceleration is the change in velocity per unit time.
    • What is the formula for acceleration?
      a=a =change in velocitytime taken \frac{\text{change in velocity}}{\text{time taken}}
    • What is the equation relating final speed, initial speed, acceleration, and distance?
      v2=v^2 =u2+ u^2 +2as 2as
    • In what units is distance measured?
      Distance is measured in metres (m).
    • In what units is time measured?
      Time is measured in seconds (s).
    • In what units are speed and velocity measured?
      Speed and velocity are measured in metres per second (m/s).
    • In what units is acceleration measured?
      Acceleration is measured in metres per second squared (m/s<sup>2</sup>).
    • What does the gradient represent in a displacement-time graph?
      • The gradient is velocity.
      • A negative gradient indicates returning to the starting point.
      • A horizontal line means it is stationary.
      • If the displacement is zero, it is back at the starting point.
      • A curved line means that the velocity is changing (accelerating/decelerating).
    • What does the gradient represent in a velocity-time graph?
      • The gradient is acceleration.
      • A negative gradient indicates deceleration.
      • If the speed is zero, it is at rest.
      • A horizontal line means constant speed.
      • The area under the line is the distance travelled.
      • A curved line means that the acceleration is changing.
    • What is a vector?
      A vector has magnitude and direction.
    • What is a scalar?
      A scalar has just a magnitude.
    • What are examples of scalars and vectors?
      Scalars:
      • Distance
      • Speed
      • Time
      • Energy

      Vectors:
      • Displacement
      • Velocity
      • Acceleration
      • Force
    • What can forces change about a body?
      Forces can change the speed, shape, or direction of a body.
    • How are forces measured?
      Forces are measured in Newtons (N).
    • What is friction?
      Friction is a force between two surfaces that impedes motion and results in heating.
    • What is air resistance?
      Air resistance is a form of friction.
    • How do you find the resultant of two or more forces acting along the same line?
      They should be added together if in the same direction and subtracted if in the opposite direction.
    • What does Newton's first law state?
      Newton's first law states that an object has a constant velocity unless acted on by a resultant force.
    • What does Newton's second law state?
      Newton's second law states that F=F =ma ma.
    • What does Newton's third law state?
      Newton's third law states that every action force has an equal and opposite reaction force.
    • How is mass defined?
      Mass is a measure of how much matter is in an object, measured in kilograms (kg).
    • What is weight?
      Weight is a gravitational force (the effect of a gravitational field on a mass).
    • What is the formula for weight?
      W=W =mg mg
    • What is the gravitational field strength on Earth?
      The gravitational field strength on Earth is 10 N/kg.
    • Where does the weight of an object act through?
      The weight of an object acts through its centre of gravity.
    • What happens to a body falling in a uniform gravitational field?
      • Initially, there is no air resistance; only weight acts on it.
      • As it falls, it accelerates, increasing speed and air resistance.
      • Resultant force downwards decreases as air resistance increases.
      • Acceleration decreases, leading to a slower increase in speed.
      • Eventually, forces balance, resulting in no acceleration and reaching terminal velocity.
    • What is thinking distance?

      The distance travelled between realizing the need to brake and pressing the brakes.
    • What factors increase thinking distance?
      Greater speed and slower reaction time due to alcohol, tiredness, or distractions.
    • What is braking distance?
      The distance travelled between pressing the brakes and the vehicle coming to a stop.
    • What factors increase braking distance?
      Greater speed or mass, and poor road or car conditions.
    • What is stopping distance?
      The stopping distance is the sum of the thinking distance and braking distance.
    • What is deformation in the context of forces?
      • Deformation is a change in size and shape of a body.
      • Elastic deformation: returns to original shape when load is removed (e.g., a spring).
      • Plastic deformation: does not return to original shape.
    • What does Hooke's law state?
      Hooke's law states that F=F =kx kx.
    • What does a linear force-extension graph indicate?
      • Indicates elastic deformation following Hooke's law.
      • The point it stops being linear is called the limit of proportionality.
      • Beyond this point, it does not obey Hooke's law.
      • The gradient represents the spring constant, k.
    • What does a non-linear force-extension graph indicate?
      • Indicates deformation not following Hooke's law.
      • After this region, the material will fracture.
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