Force and motion

• What does Newton's second law state about acceleration?

  Acceleration is proportional to resultant force.
• How is the resultant force calculated according to Newton's second law?

  Resultant force = mass × acceleration
• What is the formula for Newton's second law?

  F = m x a
• What does inertial mass measure?

  It measures difficulty in changing velocity.
• How is inertial mass defined?

  As the ratio of force over acceleration.
• How can you estimate speed and acceleration in road transport?

  By analyzing everyday transport scenarios.
• What is weight in terms of force?

  Weight is the force due to gravity.
• What causes the force of gravity near Earth?

  The gravitational field around the Earth.
• What does the weight of an object depend on?

  Gravitational field strength at its location.
• How can weight be calculated?

  Weight = mass × gravitational field strength.
• What is the relationship between weight and mass?

  Weight and mass are directly proportional.
• How is weight measured?

  Using a calibrated spring-balance.
• What happens to an object falling through a fluid?

  It initially accelerates due to gravity.
• What occurs when the resultant force on a falling object is zero?

  The object moves at its terminal velocity.
• What should you be able to do with velocity-time graphs for terminal velocity?

  Draw and interpret them for objects.
• What is the stopping distance of a vehicle composed of?

  Thinking distance and braking distance.
• How does speed affect stopping distance?

  Greater speed results in greater stopping distance.
• How can you estimate emergency stopping distances?

  By varying speeds typical for vehicles.
• What factors can affect reaction time?

  Tiredness, drugs, alcohol, and distractions.
• What is the typical range for human reaction times?

  0.2 s to 0.9 s.
• How can human reaction times be measured?

  Using various methods and recalling results.
• What should you evaluate regarding thinking distance?

  The effect of various factors based on data.
• What can affect braking distance?

  Road conditions and vehicle condition.
• What does poor vehicle condition refer to?

  Brakes or tyres in bad condition.
• What should be explained regarding emergency stopping distances?

  Factors affecting distance and safety implications.
• How does speed affect emergency stopping distance?

  Greater speed increases stopping distance.
• What happens when brakes are applied to a vehicle?

  Friction reduces kinetic energy and heats brakes.
• What is the relationship between vehicle speed and braking force?

  Greater speed requires greater braking force.
• What does greater braking force lead to?

  Greater deceleration of the vehicle.
• What can large decelerations cause?

  Brakes to overheat and loss of control.
• What dangers are caused by large decelerations?

  Overheating brakes and loss of vehicle control.
• How can you estimate forces involved in vehicle deceleration?

  By analyzing typical situations on public roads.
• What is momentum defined as?

  Momentum = mass × velocity.
• What is the principle of conservation of momentum?

  Total momentum before equals total after an event.
• What is required to change the shape of a stationary object?

  More than one force must be applied.
• What is the difference between elastic and inelastic deformation?

  Elastic deformation returns to original shape.
• What is the relationship between force and extension in elastic objects?

  Extension is directly proportional to force applied.
• What is the formula for force in terms of spring constant and extension?

  F = k e
• How does the relationship apply to compression of elastic objects?

  Same relationship applies with compression as extension.
• What happens when a force stretches or compresses a spring?

  Work is done and elastic potential energy is stored.