Physics Topic 2

• What can miles per hour be used to measure?

  the speed of vehicles
• What is used in the standard international SI system?

  metres per second (m/s)
• What is 1m/s equal to in miles per hour and km/h?

  2.24 mph, 3.6 km/h
• Examples of scalar quantities

  distance and speed
• When are scalar quantities used?

  When direction isn't important
• What is the energy of a moving body called? Measured in?

  Kinetic energy, measured in Joules
• When direction is important, what is used?

  Displacement and velocity
• What are quantities with direction called?

  Vector quantities
• What can be used to comapre different displacements and different velocities?

  Arrows of different lengths and directions
• What does a negative vector quantity mean?

  Its in the reverse direction
• What be displacement time graphs be used to describe?

  Journeys
• What is the slope and gradient of a displacement time graph equal to?

  Velocity
• Why does an object moving in a curved path with constant speed have a changing velocity?

  The direction of motion is changing
• What can velocity time graphs be used to describe?

  The same journeys
• What does this mean?

  Velocity is always zero

  
• What does this mean?

  Velocity is steady or constant

  
• What does this mean?

  The velocity is high to start with and becomes zero. Then it becomes negative, that is how the body gets back to where it started

  
• What is the slope or gradient of a velocity time graph equal to?

  Acceleration
• What is the enclosed area under a velocity time graph equal to?

  Displacement
• What is acceleration?

  The rate of change of velocity
• Is acceleration vector or scalar?

  vector
• What happens to the acceleration of an object when it is released close to the earths surface?

  It accelerates downwards
• When the acceleration is approximately 10m/s what is it called?

  acceleration due to gravity or acceleration of free fall
• What is a normal force?

  When you push at right angles to an object
• What is force measured in?

  Newtons
• Is force a scalar or a vector?

  Vector because it has a direction
• Is gravitational force always attractive?

  Yes, so there must be only one type of mass
• What is force measured in?

  Newtons (N)
• Is electric force attractive or repulsive?

  Both, so there must be two types of electric charge, positive or negative
• What is the overall force for a combination of forces called?

  Their resultant force or net force
• What happens when there is a net force on an object?

  It always accelerates
• What happens when there is no net force at all on an object or the forces are balanced?

  It never accelerates
• What is newtons first law?

  A body stays still or keeps moving at constant velocity unless an external force acts in it
• What do two forces acting in the same direction do?

  add together to produce a bigger net force
• What do two forces of the same size acting in opposite directions do?

  they dont cause acceleration, so the net force is zero
• What is newtons third law?

  For every force, there is an equal and opposite force
• What force do you experience when you push an object?

  A force of the same size and in the opposite direction
• How is net force related to acceleration?

  Acceleration is bigger when force is bigger

  It is smaller when mass is bigger
• What equation links to newtons second law?

  force = mass x acceleration
• What is resistance to acceleration called?

  Inertia