April

Distance is the total length an object in motion covers. Displacement is a vector quantity that indicates the chgange in position that an object moves in a particular direction. Average speed is the distance covered per unit time. Average velocity is the displacement divided by the time interval.

Acceleration occurs whenever there is change of speed or direction of motion.

Free fall problems can be solved like other acceleration problems by subsituting 'a' for 'g'=9.8 m/s². The sign of 'g' is (+) or (-) depending on the choice of up or down as the positive direction. It is OK to use 'g'=10 m/s² in the multiple-choice section of the exam.

A ball rolled off a horizontal table will take the same amount of time to hit the ground as another dropped from the same height.

Projectile Motion:

• a) horizontal and vertical components are independent
• b)the horizontal component of the velocity remains constant, the vertical components has constant acceleration
• c)only the vertical component of the velocity at the maximum height is zero
• d)for projectiles fired at an angle you may assign negative signs to all vectors going down.