paper 2

• What is a force?

  A push or pull on an object
• What are the two types of forces?

  Contact and non-contact forces
• What is the significance of electrostatic repulsion in contact forces?

  It explains why contact forces occur
• What is a normal contact force?

  The force exerted perpendicular to a surface
• How can forces be represented?

  With vectors showing direction and magnitude
• What does the length of a force vector represent?

  The magnitude of the force
• What is a resultant force?

  The overall force acting on an object
• How do you find the resultant force when two forces act in opposite directions?

  Add the vectors, using negatives for opposite directions
• How do you find the resultant force when vectors are at right angles?

  Use Pythagoras' theorem
• What is Newton's first law of motion?

  An object will not change its motion unless acted upon
• What is a scalar quantity?

  A quantity with magnitude but no direction
• What is weight?

  The force due to gravity on an object
• How is weight calculated?

  Weight = mass × gravitational field strength
• What is the gravitational field strength on Earth?

  9.8 N/kg
• What must be true for forces to be balanced when lifting an object?

  The upward force must equal the weight
• What is the equation for work done?

  Work done = force × distance moved
• How can you calculate gravitational potential energy gained?

  GPE = mass × gravitational field strength × height
• What does Hooke's law state?

  Force = spring constant × extension
• What is the unit for spring constant?

  Newtons per meter (N/m)
• What does it mean for a material to stretch elastically?

  It returns to its original shape after force removal
• What is the principle of moments?

  Moments clockwise equal moments anticlockwise
• What is the equation for pressure?

  Pressure = force / area
• What is the unit for pressure?

  Pascals (Pa)
• How does pressure change with depth in water?

  Pressure increases with greater depth
• How is gas pressure created?

  By collisions of gas particles with surfaces
• What factors increase gas pressure?

  More gas, reduced volume, or increased temperature
• What happens to atmospheric pressure with altitude?

  It decreases with higher altitude
• How is speed measured?

  In meters per second (m/s)
• What is the difference between speed and velocity?

  Velocity includes direction; speed does not
• How do you calculate speed or velocity from a distance-time graph?

  Gradient of the graph gives speed or velocity
• What does a negative gradient on a speed-time graph indicate?

  The object is decelerating
• What is the unit of acceleration?

  m/s²
• What is the acceleration of a falling object?

  9.8 m/s²
• How can you find the distance traveled from a velocity-time graph?

  Calculate the area under the graph
• What is Newton's second law of motion?

  F = ma (force equals mass times acceleration)
• How do you determine the correct equation for Newton's laws?

  Identify the variables and rearrange as needed
• What is inertia?

  The tendency of an object to resist changes in motion
• How does Newton's third law apply to a ball and the Earth?

  The ball pulls the Earth up as it falls
• What does Newton's third law state?

  For every action, there is an equal and opposite reaction
• What is the overall stopping distance of a car composed of?

  Thinking distance plus braking distance