Newtons laws

• What happens to the speed and/or direction of a body when the resultant force is not zero?

  The speed and/or direction of the body changes.
• Why does an object moving in a circular orbit at constant speed have a changing velocity?

  Because the direction of the object is continuously changing.
• What is the resultant force that acts on an object moving in a circle called?

  Centripetal force.
• What is required for motion in a circle?

  A resultant force known as centripetal force that acts towards the center of the circle.
• According to Newton's First Law, what will happen to a stationary object if no external force acts on it?

  The object will remain at rest.
• What does Newton's First Law state about an object in motion?

  An object will continue to move at the same speed and direction unless an external force acts on it.
• What happens to an object if there is no resultant force acting on it?


  The object stays still or keeps moving at the same speed and in the same direction.
• What is the relationship between resultant force and acceleration according to Newton's Second Law?

  If there is a resultant force acting, an object will accelerate in the direction of the resultant force.
• What factors does the acceleration of an object depend on according to Newton's Second Law?

  The size of the resultant force and the mass of the object.
• What is the formula for calculating resultant force?

  Resultant force = mass x acceleration.
• If the mass of an object is 2 kg and it accelerates at $3 \text{ m/s}^2$, what is the resultant force acting on it?


  $F =$$m \times a =$$2 \text{ kg} \times 3 \text{ m/s}^2 =$$6 \text{ N}$
• What does Newton's Third Law state about action and reaction forces?


  Every action has an equal but opposite reaction force.
• How do action and reaction forces relate to interacting objects?

  They occur in pairs between two interacting objects.
• What is inertial mass?


  Inertial mass is a measure of an object's resistance to acceleration when a force is applied.
• How does the size of the resultant force affect acceleration?

  A larger resultant force results in greater acceleration.