Forces and Interactions

• Push, pull, twist, tensile, compression and friction are examples of forces.
• Forces are pushes or pulls that can make things move, change direction, or stop.
• Forces are interactions between objects, like when you push a book or pull a door.
• Forces can be strong or weak, and they can act in different directions, such as up, down, left, right, or even at angles.
• Forces are described in terms of their strength and direction, and they follow Newton's laws of motion, which help us understand how objects move in response to these forces.
• Push is a force that is applied to an object to move it away from the point of application, for example, pushing a shopping cart.
• Pull is a force that is applied to an object to move it toward the point of application, for instance, pulling a door to open it.
• Twist or Turn is a rotational force that causes an object to rotate around its axis, this force is applied perpendicular to the axis of rotation.
• Tensile forces stretch an object by applying a force that tries to pull it apart, for example, stretching a rubber band.
• Compression forces push or squeeze an object, trying to make it shorter or more compact, this force is applied in the direction of the object's compression.
• Newton’s second law is stated as: a = acceleration, m = mass.
• F = applied force, N = net force.
• The unit measurement of p is kg⋅m/s.
• The total momentum of the system cannot change.
• Total momentum is always constant.
• There are two types of collisions, inelastic and elastic.
• After a collision, two objects of equal mass of 10 kg have different momentums.
• Elastic collisions occur when two objects strike each other but do not stick together.
• The equation for momentum is: p = momentum, m = mass, and v = velocity.
• The law of conservation of momentum states that the total momentum of two objects before the collision is equal to the total momentum of two objects after the collision.
• Momentum is an important factor when looking at collisions.
• An elastic collision occurs when the two objects strike together after the collision.
• Friction is a force that opposes the relative motion or attempted motion of two surfaces in contact, it can be both a push and a pull force, depending on the direction of motion.
• Simple machines are basic tools that make it easier to do work, in scientific terms, work is the activity of a force being applied to move an object.
• Simple machines usually require less force to accomplish tasks like lifting, pushing, or pulling things, examples include levers, wheels and axles, and inclined planes.
• These machines simplify our daily activities by providing mechanical advantages.
• A lever is a rigid bar that pivots on a fulcrum, providing a mechanical advantage for lifting or moving objects, examples include seesaw, crowbar, scissors.
• Bolt, jar lid, spiral staircase are basic simple machines that simplify various tasks and are fundamental components in the design of more complex machinery and tools.
• A net force is the sum of two or more forces being applied to set an object in motion.
• A knife, axe, doorstop screw is an inclined plane wrapped around a cylinder or rod that can be turned to hold objects together or lift them.
• When θ (the angle between force and displacement) is 0 degrees, cos(0) = 1, indicating that the force is parallel to the direction of motion, resulting in maximum work done and equal to zero when θ = 90 degrees, cos(90) = 0, meaning the force is perpendicular to the direction of motion, resulting in zero work done.
• Work is a type of energy in scientific terms, work is the activity of a force being applied to move an object.
• An unbalanced force occurs when the net force on an object doesn't add up to zero, leading to a change in the object's motion.
• Newton’s First Law of Motion, also known as the law of inertia, states that an object will remain at rest or move at a constant velocity unless acted upon by an external force.
• Newton’s Second Law of Motion states that if an object is acted upon by a force, it will accelerate in the direction of that force.
• A flagpole, elevator, clothesline wedge is a triangular-shaped object used to split or separate things by applying force.
• The amount of force necessary to push or pull an object depends on its mass.
• If an object cannot be moved by one force, an additional force may be added that results in the object being moved.
• The equation for work is W = F * d * cosθ.
• A wheel and axle is a wheel attached to a rod (axle) that enables the movement of loads with reduced effort, examples include car wheel, doorknob, bicycle.