Calculate the acceleration that this object experiences 30 kg 150 N
Newton’s 2 nd Law (N2L) When F net = 0, acceleration = 0 The object is in equilibrium All forces acting on the object are balanced
If an object dropped on Earth were able to fall without any air resistance, it would accelerate at a rate of g = 9.8 m/s 2 The only force acting on the object would be gravitational force Therefore, according to N2L F net = F W = ma Since Earth’s gravitational acceleration is a constant it has its own variable, g Therefore, F W = mg = m(9.8 m/s 2 ) Remember: weight ≠ mass!!!
Since mass is used to calculate weight, mass and weight can never be equal. › Weight is dependent on location (on Earth, on the Moon, in space, etc) › Mass only depends on the amount of matter Your mass would be the same on Earth or on the moon
Mass is a scalar (same amount no matter where you are) › measured in kilograms Weight is a force (the force of gravity pulling on an object) and a vector › Weight is measured in Newtons
All things fall to Earth with the same acceleration = g So, F W = mg Why don’t things appear to fall at the same rate?? Air Resistance The air must be moved out of the way in order for an object to move through it.
Air density- more particles to move out of the way Speed of the object- particles must be moved out of the way faster Surface area of the object- more particles must be displaced at once.
Terminal velocity – highest speed reached while falling on Earth › Occurs when F w = F air › F air increases as your speed increases until it equals F w › When F w = F air the object is in equilibrium
1. One kilogram weights 2.2 pounds. Determine your mass using this as a conversion factor 2. Use your mass to calculate your weight