5.1.8 Balanced & Unbalanced Forces

• What are forces defined as?

  Forces are pushes or pulls that can cause an object to move, change direction, speed up, slow down, or change shape.
• How are forces measured?

  Forces are measured in Newtons (N) and have both magnitude and direction.
• What makes forces vector quantities?

  Forces are vector quantities because they have both magnitude (size) and direction.
• What are balanced forces?

  Balanced forces occur when all the forces acting on an object are equal in size but opposite in direction.
• What happens to the effects of balanced forces?

  When forces are balanced, their effects cancel each other out.
• What is the net force when forces are balanced?

  • The total or resultant force is zero.
• What is the effect of balanced forces on a stationary object?

  If the object is at rest, it will remain at rest.
• What is the effect of balanced forces on a moving object?

  If the object is moving, it will continue to move at the same speed and in the same direction.
• Give an example of balanced forces.

  A book resting on a table has balanced forces.
• What balances the downward gravitational force on a book resting on a table?

  The upward normal force from the table balances the downward gravitational force.
• What is another example of balanced forces in motion?

  A car moving at a constant speed has balanced forces.
• What forces are balanced when a car moves at a constant speed?

  The forward driving force is balanced by the resistive forces like air resistance and friction.
• What are unbalanced forces?

  Unbalanced forces occur when the forces acting on an object are not equal, causing acceleration.
• What is the net force when forces are unbalanced?

  • The total or resultant force is not zero.
• What happens to an object at rest when unbalanced forces act on it?

  If the object is at rest, it will start to move in the direction of the resultant force.
• What happens to a moving object when unbalanced forces act on it?

  If the object is already moving, it will accelerate in the direction of the resultant force.
• Give an example of unbalanced forces.

  A car accelerating has unbalanced forces.
• What causes a car to accelerate?

  The driving force is greater than the resistive forces, causing the car to speed up.
• What happens to a falling object in terms of forces?

  The weight of the object is greater than the air resistance, so the object accelerates downwards.
• What does Newton's First Law of Motion state?

  An object will remain at rest or move at a constant velocity unless acted upon by a resultant force.
• How do balanced and unbalanced forces relate to Newton's First Law?

  • Balanced Forces: No resultant force, so the object’s state of motion doesn’t change.
  • Unbalanced Forces: A resultant force causes the object to accelerate.
• How is the resultant force calculated?

  • Add vectorially all individual forces acting on the object.
  • If forces act in the same direction, add their magnitudes.
  • If forces act in opposite directions, subtract the smaller force from the larger one.
• What are the practical implications of understanding balanced and unbalanced forces?

  • Vehicle Safety: Helps in designing safe vehicles that maintain control.
  • Engineering: Ensures structures can withstand unbalanced forces without collapsing.
• What is the summary of balanced and unbalanced forces?

  • Balanced Forces: Equal and opposite forces resulting in no change in motion (net force = 0).
  • Unbalanced Forces: Unequal forces leading to acceleration in the direction of the resultant force (net force ≠ 0).