AP Physics Summer Work

Scalars: A quantity (magnitude) w/out direction.

    Ex) Distance: The total length traveled by an object, independent of the direction.

• Just add to find the total distance

• Speed: How fast/slow an object is moving; the total distance traveled in a certain time.

  

Vectors: A quantity that has both magnitude and direction.

    Ex) Displacement: change in the position of an object (path does not matter).

• Displacement is relative to an axis: ‘x’ is horizontal displ. and ‘y’ is vertical displ.

  • Displacement = Final - Initial;  Δx = x_f - x_i or Δy = y_f - y_i

• Directions are either positive or negative, or in angles.

• To add, you have to use vector rules. (Use Pythagorean theorem)

• Velocity: How fast the position of an object changes; the rate of change of displacement; describes the speed of an object with its direction.

  • Negative velocity indicates direction, not speed.

  • The direction of velocity and displacement always match.

• Force: The interaction between two objects; either a push or pull.

  • A net force is what causes all accelerations.

  • Net Force: The sum of all forces acting upon an object.

  • A net force of 0 means that there is no change in motion, or no acceleration; this means that all forces acting on an object are balanced.

  • If the net force is greater than 0, it means that the forces are unbalanced; there is a change in velocity, or the object is accelerating.

• Acceleration: change in velocity; the rate at which an object’s velocity changes.

  • NOT AN INDICATION OF SPEED.

  • Only measures changes in velocity (speeding up or slowing down), or direction.

  • Equation (only holds for constant acceleration):

    

• Constant velocity means that the acceleration is 0; meaning there is no change in the current motion of the object.

• Constant acceleration means that the rate at which the velocity of an object changes is constant over a duration.

• The velocity and displacement of an object will always be in the same direction.

• If the direction of the velocity and acceleration are the same, then the object is speeding up in that direction; if they are not the same, then the object is slowing down in the direction of the velocity.

  

• BE SPECIFIC WHEN DESCRIBING THE ACCELERATION OF AN OBJECT.

  • Formula: “speeding up/slowing down in the positive/negative direction.”