1 mechanical motion: the change of object position. Motion and stillness are relative. 3 reference object: the standard object selected when learning mechanical movement. 4 Uniform linear motion: Uniform linear motion. Speed: In uniform linear motion, speed is equal to the distance traveled by the moving object in unit time. Speed is a physical quantity representing the speed of an object. The speed calculation formula is: v=s/t 7 variable speed movement: the speed of a moving object is variable, and this movement is called -8 average speed: the average speed of an object passing through a certain distance. Chapter V Reflection of Light 1 Light Source: An object that can emit light is called a light source. 2 1878 American Edison invented incandescent lamp 3 light: the straight line indicating the direction of light propagation is called light. Law of Light Propagation: Light travels in a straight line in the same uniform and transparent medium. 5 The speed of light: 3* 100000 km/s is three-quarters of this speed in water and two-thirds of that in glass. 7 normal: the line perpendicular to the mirror through the incident point. Incident angle: the angle between incident light and normal. Reflection angle: the angle between the reflected light and the normal. Law of reflection: reflected light, incident light and normal are in the same plane; Reflected light and incident light are separated on both sides of the normal; The reflection angle is equal to the incident angle. 10 optical path is reversible. 1 1 diffuse reflection: If the mirror surface is uneven, the reflected light is not parallel after the parallel light is incident, but exits in all directions. Specular reflection: If the mirror is smooth, the reflected light is still parallel to the virtual image of 12 after the parallel light is incident: it is not the actual light, but the image formed by the convergence of the reverse light along a long line. Real image: the image formed by the convergence of actual light is called real image. Four characteristics of 13 flat mirror imaging: the image formed by 1 flat mirror is a virtual image; The image formed by the plane mirror is equal to the size of the object; 3 The distance from the image in the mirror to the mirror is equal to the distance from the object to the mirror; The line between the image and the object is perpendicular to the mirror. 14 will use vertical equidistant and light path diagram to find the image of the object. The key is the optical path diagram method. 15 spherical mirror: a mirror that reflects with a part of the spherical surface. 16 concave mirror: a spherical mirror that uses the inner surface of a spherical surface for reflection. Convex mirror: a spherical mirror that uses the outer surface of a sphere to reflect. 17 function of spherical mirror: concave mirror can converge light into light. In addition, the light emitted by the focused light source can be emitted in parallel after concave mirror reflection. A convex mirror can diffuse light, but it can expand the field of vision. 18 concave mirror focus: The point where the parallel light rays directed to concave mirror converge after reflection is called the focus. Chapter VI Refraction of Light 1 Refraction of Light: When light is injected from one medium into another, the propagation direction will generally change this phenomenon. 2 Refraction angle: the angle between refracted light and normal. 3 refraction law: 1 refracts light, and the incident light and the normal are in the same plane; 2 refracted light and incident light are separated on both sides of the normal; When light enters water or other media from air, the refraction angle is smaller than the incident angle, and when light enters air from water or other media, the refraction angle is larger than the incident angle. When light is vertically incident on the interface, the propagation direction remains unchanged. Note: The refraction angle increases with the increase of incident angle and decreases with the decrease of incident angle. The refraction of the optical path is also reversible. 5 convex lens: the lens with thick middle and thin edge is convex lens. Concave lens: A lens with a thin center and a thick edge is a concave lens. Main optical axis of lens: a straight line passing through the centers of two spherical surfaces. 7 optical center: the point where the propagation direction remains unchanged after light passes through is called the optical center. The function of convex lens: it converges light, so it is also called convergent lens. Convex lens focus: After the parallel rays are refracted by the convex lens, the refracted rays will converge at the focus on the main optical axis. This is the focus of the convex lens. The function of concave lens: divergent light. 10 parallel light is refracted by a convex lens and then converged on the focal point. On the contrary, the parallel light refracted from the focal point is refracted by the concave lens, and the reverse extension line of the refracted light passes through the virtual focal point. If the extension line of incident light passes through the virtual focus, it must be parallel to the main optical axis after refraction. 1 1 camera principle: u >；; 2f f<v & lt2f can form an inverted reduced real image when the distance from the object to the convex lens is more than twice the focal length. 12 slide projector principle: f; When resistance pushes an object to move at a uniform speed, thrust = resistance 9 Friction: the force on the contact surface that hinders the relative motion of the object. 10 factors affecting sliding friction: 1 pressure. 2 roughness of contact surface. * Try to increase beneficial friction and reduce harmful friction. 1 1 Ways to increase beneficial friction: 1 Make the contact surface rougher. 2 increase the pressure. 12 methods to reduce harmful friction: 1 make the contact surface smoother. 2. Use rolling instead of sliding to make the contact surface out of contact, that is, use lubricating oil or air cushion.