Chapter 4 Summary
• Newton's Second Law states that the acceleration of an object is directly proportional to the Net Force applied to it and inversely proportional to its mass. This is commonly written as a = ΣF/m or, more commonly ΣF = ma.
• Weight is a force. It always acts downward and it is calculated by taking the object's mass (in Kg) and multiplying it by the acceleration due to gravity (g, in m/s/s).
• The reason why all objects accelerate downward at the same rate can be explained by Newton's Second Law. A large object has a lot of mass and also a lot of weight. A small object has less mass and less weight. The ratio between weight and mass, however is the same for both:
F/m = a = F/m
• By using Free Body Diagrams to find the net force on an object, the acceleration of the object can be calculated.
• Pressure is Force being applied over some Area.
• Newton's Third Law states that when two objects exert force on each other (either by contact or over a distance), the forces are equal in magnitude and opposite in direction. Forces always come in pairs.
• When two objects collide, the force felt by each object is the same. The resulting acceleration of the object depends on the object's mass.
ma = F = ma
• Friction always opposes the motion of an object.
• Friction is always parallel to the surface while the normal force is always perpendicular.
• To change directions, a centripetal force is applied to an object.
Equations
• ΣF = ma
• Weight = mg
• Pressure = Force / Area ( P = F/A)
• Weight is a force. It always acts downward and it is calculated by taking the object's mass (in Kg) and multiplying it by the acceleration due to gravity (g, in m/s/s).
• The reason why all objects accelerate downward at the same rate can be explained by Newton's Second Law. A large object has a lot of mass and also a lot of weight. A small object has less mass and less weight. The ratio between weight and mass, however is the same for both:
F/m = a = F/m
• By using Free Body Diagrams to find the net force on an object, the acceleration of the object can be calculated.
• Pressure is Force being applied over some Area.
• Newton's Third Law states that when two objects exert force on each other (either by contact or over a distance), the forces are equal in magnitude and opposite in direction. Forces always come in pairs.
• When two objects collide, the force felt by each object is the same. The resulting acceleration of the object depends on the object's mass.
ma = F = ma
• Friction always opposes the motion of an object.
• Friction is always parallel to the surface while the normal force is always perpendicular.
• To change directions, a centripetal force is applied to an object.
Equations
• ΣF = ma
• Weight = mg
• Pressure = Force / Area ( P = F/A)