Chapter 4: Force and Motion Test Review
8th Science
Motion, Speed & Velocity
Speed is a measurement that describes the distance a moving object travels per unit of time.
Speed = Distance/Time
Velocity describes and object’s speed and the direction of its motion.
Slope is the steepness of a line on a graph.
Acceleration
Acceleration is the rate at which velocity changes.
Acceleration= Final speed-Initial speed/Time
The SI unit for acceleration is m/s2.
Know what acceleration looks like on a distance vs time graph and on a speed vs time graph.
The Nature of Force
A force is a push or pull.
Know how to calculate net force from a given scenario. (Review net force notes in ISN.)
If the forces are going in the same direction, you add them, if they are going in opposite directions, you subtract.
Kinetic energy is the energy that results from the motion of an object.
Review potential and kinetic energy notes and be able to identify each in a given example.
Friction & Gravity
Friction is the force that 2 surfaces exert on each other when they rub against each other.
Weight is a measure of the force of gravity on an object.
Newton’s Laws (Be able to tell whether a scenario is an example of Newton’s 1st, 2nd or 3rd law.)
Newton’s First Law (law of inertia) states that an object at rest will remain at rest unless acted upon by a nonzero net force (unbalanced force). An object moving at a constant velocity will continue moving at a constant velocity unless acted upon by an nonzero net force (unbalanced force).
Inertia is the resistance to change in motion. The greater the mass of an object, the greater the inertia.
Newton’s Second Law of Motion (law of acceleration) states that an object’s acceleration depends on its mass and on the net force acting on it.
The formula for the 2nd law is Force=Mass x Acceleration
The SI unit for force is Newtons (N).
The SI unit for mass is kilograms (kg).
The SI unit for acceleration is meters per second per second (m/s2).
Be able to solve problems using the formula. (Review notes in ISN.)
Newton’s Third Law of Motion (law of action-reaction) states that if one object exerts a force on another object, then the second object exerts a force of equal strength in the opposite direction of the first object.