Welcome to Weber Physics Online This power point will help give you a basic start to understanding the laws of physics and it will also list the Utah State Physics Standards and vocabulary to aid in your instruction. (vocabulary will be bolded on the core outline) Remember this is a basic power point so feel free to look at other sources for additional information.(internet, books, movies etc.)
Utah State Core Standard Objective 2: Using Newton’s second law, relate the force, mass, and acceleration of an object. 1.Determine the relationship between the net force on an object and the object’s acceleration. 2.Relate the effect of an object’s mass to its acceleration when an unbalanced force is applied. 3.Determine the relationship between force, mass, and acceleration from experimental data and compare the results to Newton’s second law. 4.Predict the combined effect of multiple forces (e.g., friction, gravity, and normal forces) on an object’s motion.
Newton’s 2 nd Law Discussion of Acceleration
Newton’s 2 nd Law Acceleration is change in velocity / time interval Unbalanced forces cause acceleration Increasing net force increases acceleration proportionally Acceleration ~ net force
Relationship between mass and acceleration Increasing mass decreases acceleration More massive objects require more force to accelerate them Inverse relationship. Acceleration ~ 1 / mass
Newton’s 2 nd Law Combines both effect of force and effect of mass on acceleration States: Acceleration produced by net force is directly proportional to magnitude of net force, is in direction of net force, and is inversely proportional to mass of object Acceleration = net force / mass
Solve this Problem Mass = 5 kg Let’s assume that the wheels of a 5- kg car apply 10 N of force. What is the net force if friction and drag are negligible? What is the acceleration of the car? Force= MA 10= 5A Acceleration =
Solve this Problem Mass = 6 kg What is the net force if the wheels of the 5-kg car apply 10 but a 1-kg parachute applies 3 in the other direction? What is the acceleration of the car? Acceleration= F/M Acceleration= 3/6 Acceleration =
Solve This One Mass = 10 kg A rocket is added to the car and applies an additional force of 10. The wheels still apply 10 N. What is the net force if the parachute continues to apply 7 in the other direction? The total mass of the car, rocket and parachute is 10 kg. What is the acceleration of the car? Acceleration= F/M Acceleration=13/10 Acceleration =
Free Fall In free fall, more massive objects experience more force from gravity than smaller objects So F / m = F / m
Terminal Velocity Downward pull of gravity = upward push of air resistance Acceleration = 0 Net force = 0 Velocity is constant
Free fall and Terminal Velocity