Physics 10 # WA 1 PDF

PHYSICS 10 # WA 1 NEWTON LAWS OF MOTION - - Mass is a measure of inertia. - The net force acting on it and inversely proportional to its mass. This LAW OF INERTIA : “An object will relationship is often expressed with the...

PHYSICS 10 # WA 1 NEWTON LAWS OF MOTION - - Mass is a measure of inertia. - The net force acting on it and inversely proportional to its mass. This LAW OF INERTIA : “An object will relationship is often expressed with the remain at rest when in motion and will formula 𝐹 = 𝑚 𝑎 F=ma, where 𝐹 F is continue to move with constant the force, 𝑚 m is the mass, and 𝑎 a is velocity unless acted upon by an the acceleration. external force.” 1. MOVING ON WITH - Inertia is a term used to NEWTON (THE NATURE measure the ability of an OF FORCE) object to resist a change in its state of motion - FORCE : The push - An object with a lot of inertia and pull exerted by takes a lot of force to start or a body on another stop; an object with a small body; the effect of amount of inertia requires a which is to tend to change the state of small amount of force to start motion of the body on which it acts. or stop - It is a vector quantity - SI unit is Newton (N) FUNDAMENTAL FORCE : - Gravitational force : Attraction between objects by virtue of their masses and is responsible for weights of bodies. - Electromagnetic force : Attractive or repulsive force between charged bodies - Strong nuclear force : Holds constituencts of the nucleus of an atom - Weak nuclear force : Plays a role in radioactive decay Examples of Inertia : - A book at the top of a table - Riding a jeepney, the vehicle suddenly stops - ROding a jeepney, the vehicle suddenly accelerates - Objects hitting a barrier 2. MOVING ON WITH NEWTON 1ST LAW OF MOTION. (LAW OF INERTIA) - INERTIA : The property of a body that tends to resist a change in its state of motion 3. MOVING WITH NEWTON : 2ND LAW OF LAW OF ACCELERATION : “An unbalanced MOTION (LAW OF ACCELERATION) force acting on a body produces acceleration. The acceleration is directly proportional to the - FORCE : The product of mass (m) and unbalanced force and inversely proportional to acceleration (a) the unbalanced force and inversely - F = ma proportional to the bass of the body. The acceleration acts in the same direction as the Acceleration versus Mass (Force is unbalanced force. Constant) 4. MOVING ON WITH NEWTON : 3RD LAW - If an object has more mass, te object OF MOTION (LAW OF INTERACTION) accelerates at a slower rate - ACTION-REACTION - : Equal in magnitude, but oppositely directed - : Acting in two different bodies and will never cancel out. - Always comes in pairs - Equal in magnitude, but oppositely directed. - - Acting in two - - if more force is applied to an object, different bodies the object accelerates at a higher rate. and will never cancel out LAW OF ACCELERATION : - Always come in pairs FRICTION : The resistance to motion between two materials in contact. - Static Friction : sufficient to prevent relative motion between surfaces in contact. - KInetic Friction - There is relative motion between surfaces in contact - Rolling Friction - one surface rotates as it moves over another without sliding nor slipping at the point or area of contact. IMPORTANCE : Explains the relationship between the net force, mass, and acceleration of an object FORCE : A push or pull acting on an object UNBALANCED FORCES : Forces that when that changes the motion of an object added DO NOT cancel out. They cause a change in motion of the object. F=ma : Force can cause acceleration - It describes the relationship among Fnet = +30N + (-10N) = +20 N force, mass, acceleration as stated in the second law of motion MASS VS WEIGHT - MASS : is the amount of matter that FORCE - Measured in unit Newton (N) an object possesses. It does not change with location - WEIGHT : Is the gravitational force that a large body (EX: Planet) exerts on another object WEIGHT (W): - Weight is a Force! It is measured in N - F = ma ; W = ma (due to gravity) TWO GENERAL TYPES OF FORCES - W = mg ; where g = 9.8m/s^2 ; mass - Contact is in kg - Non-Contact - Weight does change with location! - (“g” will change with location.) CONTACT FORCES : Forces that act through direct contact between two objects, Applied BASICALLY ; always multiply the M with force, Friction, Normal Force, Tension 9.8m/s^2 if you’re looking for the weight NON-CONTACT FORCES : Forces that can act W = mg (note : mg means m x g) over distances, Long or Range forces, Gravity W = (45kg)(9.8m/s^2) and Electromagnetic force W = 441 N FORCE IS A VECTOR QUANTITY : It has Normal Force (Fn) MAGNITUDE & DIRECTION - Force exerted by a surface to support - Direction of force is the same as the weight of an object resting on it. direction of acceleration - Always directed perpendicular (or “normal”) to the surface upon which NET FORCE (Fnet) the object rests. - When multiple forces are acting on an - Acts to support the W of the object and object. The net force is the amount of prevent it from sinking into the force that is left after adding all the surface. forces on the object. - The Net Force (Fnet) is also the Resultant Force (Fr) BALANCED FORCES - Forces that are equal and opposite so that they cancel out. 10N EAST -> Ffs then it will move KINETIC FRICTION (Ffk) - Acting while in motion or sliding - Determines the smoothness of motion - High Ffk = Hard to slide = Easier to walk (Study FBA in slides, page 56.) What reduces Friction? : - Wheels or rollers - Lubricants (oil, etc) - Sanding the surface. AIR RESISTANCE (Fair) - Also called Drag (FD) - Force air exerts against a moving object - As an object moves, Fair slows it down - The faster the objects motion, the greater the Fair exerted against it - If an object is accelerating as it falls, then Fnet is not 0. - If an object is not accelerating as it falls, then Fnet = 0 - TERMINAL VELOCITY : Constant Velocity that a falling object reaches when the force of gravity pulling it downwards is balanced by the force of air drag pushing upward. W=Fair