Physics Chapter 3: mass and weight
types of forces
non contact forces
contact forces
electrostatic force, the attractive pull or repulsive push between electric charges
magnetic force, the attractive pull or repulsive push between magnets
gravitational force, the pull exerted by earth's gravity on any object, also known as weight
air resistance, the frictional force exerted by the air that opposes the motion of moving objects
normal force, the push exerted by a surface on an object pressing on it, this push is ALWAYS PERPENDICULAR to the surface
friction, the force that opposes or tends to oppose motion between surface in contact
tension, the pull exerted by a stretched string, spring, or rope on an object attached to it
weight
mass
measure of the amount of matter in a body
measured in kilogram(kg), the mass of a body does not change with location or shape
the gravitational force acting on an object that has mass, measured in newton
gravitational field, a region in which a mass experiences a force due to gravitational attraction, gravitational field strength is defined as the gravitational force per unit mass placed at that point, gravitational field strength can be measured by taking the weight and dividing by the mass of an object
acceleration due to gravity, on earth, the gravitational field strength is 10N/kg, and the acceleration is F=ma, the acceleration of free fall can be calculated as g=W/m=10m/s2
mass, an amount of matter, scalar quantity magnitude only, measured in kilograms, not affected by gravitational field strength, measured with a beam balance or an electronic presence
weight, gravitational force, vector quantity has both magnitude and direction, measured in newton, affected by gravitational field strength, measured with a spring balance
upthrust force, upward force exerted by a fluid on an object immersed in it, it is because of upthrust that one feels lighter inside a swimming pool
gravitational field strength and acceleration of free fall
gravitational field strength is equal to weight/mass
for a free-falling object, the only force acting on it is its weight, acceleration = weight/mass, acceleration of free fall is the same as the gravitational field strength