Newtons Laws

• What is mass?

  The amount of matter in an object
• What is mass measured in?

  Kilograms
• What is weight?

  The force of gravity on your mass
• What is gravity?

  The force of attraction between all masses
• Whats another name for the force caused by the Earths mass attracting an objects mass?

  Weight
• What’s the equation for the weight of an object?

  $W=$$m*$$g$
• What letter is gravitational field strength given in an equation?


  g
• The moon has a smaller mass than the earth
• The moon has a smaller gravitational field strength than the earth.
• What is inertia?

  Resistance to change in motion.
• What’s an example of how inertia works?

  Going forward when the bus has stopped
• What is Newtons First Law?

  A body will continue in it’s direction/at rest until acted upon by another force
• What does Newton’s first law mean?

  That balanced forces will have no effect on the motion of an object
• What are objects before another force acts upon them?

  • still
  • moving at a constant rate
  • hovering/floating
• What happens if the force moving forward is larger than backward?

  You accelerate
• What happens if the forces are equal?

  You remain at a constant speed
• What happens if forces pulling you back are larger than forward?

  You decelerate
• What is Newton’s second law?

  When forces acting on an object don’t balance the resultant force causes it to accelerate in that direction
• What do unbalanced forces cause?

  • acceleration
  • deceleration
  • change in direction
• What’s the equation for Newton’s second law?

  F = ma (Force equals mass times acceleration)
• Whats the relationship between mass and acceleration?

  Inversely proportional
• What’s the greek letter for resultant force?

  Σ (Sigma)
• What happens when objects move faster?

  Air resistance/drag increases
• What happens as drag forces increase?

  The resultant force is reduced
• What happens when drag forces are the same as the weight or thrust?

  The forces become balanced
• What happens when forces become balanced?

  The objects stops accelerating and moves at a constant speed
• What is constant speed also known as?

  Terminal speed/velocity
• What does a rising or falling line show on a graph?

  The velocity is changing
• What does acceleration and deceleration mean in terms of force?

  The forces must be unbalanced
• What does a horizontal line mean?

  The speed is constant/terminal
• What does moving through the air cause?

  Collisions with air molecules
• Why is some kinetic energy converted to heat when skydiving?

  There is friction between the air molecules and the body
• Why do feathers and hammers not hit the ground at the same time?

  Air resistance affects the feather more than the hammer
• What is Newtons third law?

  If body A exerts a force on body B, body B exerts an equal and opposite force on body A