`color{red}✍️ ` In mechanics, we encounter several kinds of forces. The gravitational force is, of course, all pervasive.
`color{red}✍️ ` Every object on the earth experiences the force of gravity due to the earth. Gravity also governs the motion of celestial bodies. The gravitational force can act at a distance without the need of any intervening medium.
`\color{fuchsia} {★ \mathbf\ul"Contact Forces"}`
`color{red}✍️ ` A contact force on an object arises due to contact with some other object: solid or fluid.
`color{red}✍️ ` When bodies are in contact (e.g. a book resting on a table, a system of rigid bodies connected by rods, hinges and other types of supports), there are mutual contact forces (for each pair of bodies) satisfying the third law.
`color{red}✍️ ` The component of contact force normal to the surfaces in contact is called normal reaction.
`color{red}✍️ ` The component parallel to the surfaces in contact is called friction.
`color{red}✍️ ` Contact forces arise also when solids are in contact with fluids. For example, for a solid immersed in a fluid, there is an upward buoyant force equal to the weight of the fluid displaced. The viscous force, air resistance, etc are also examples of contact forces (Fig. 5.9).
`\color{fuchsia} {★ \mathbf\ul"Tension Force"}`
`color{red}✍️ ` The tension force is the force that is transmitted through a string, rope, cable or wire when it is pulled tight by forces acting from opposite ends.
`color{red}✍️ ` The tension force is directed along the length of the wire and pulls equally on the objects on the opposite ends of the wire.
`color{red}✍️ ` For an inextensible string, the force constant is very high.
`\color{fuchsia} {★ \mathbf\ul"Spring Force"}`
`color{red}✍️ ` When a spring is compressed or extended by an external force, a restoring force is generated.
`color{red}✍️ ` This force is usually proportional to the compression or elongation (for small displacements). The spring force `F` is written as `F = – k x` where `x` is the displacement and `k` is the force constant.
`color{red}✍️ ` The negative sign denotes that the force is opposite to the displacement from the unstretched state.
`color{red}✍️ ` In mechanics, we encounter several kinds of forces. The gravitational force is, of course, all pervasive.
`color{red}✍️ ` Every object on the earth experiences the force of gravity due to the earth. Gravity also governs the motion of celestial bodies. The gravitational force can act at a distance without the need of any intervening medium.
`\color{fuchsia} {★ \mathbf\ul"Contact Forces"}`
`color{red}✍️ ` A contact force on an object arises due to contact with some other object: solid or fluid.
`color{red}✍️ ` When bodies are in contact (e.g. a book resting on a table, a system of rigid bodies connected by rods, hinges and other types of supports), there are mutual contact forces (for each pair of bodies) satisfying the third law.
`color{red}✍️ ` The component of contact force normal to the surfaces in contact is called normal reaction.
`color{red}✍️ ` The component parallel to the surfaces in contact is called friction.
`color{red}✍️ ` Contact forces arise also when solids are in contact with fluids. For example, for a solid immersed in a fluid, there is an upward buoyant force equal to the weight of the fluid displaced. The viscous force, air resistance, etc are also examples of contact forces (Fig. 5.9).
`\color{fuchsia} {★ \mathbf\ul"Tension Force"}`
`color{red}✍️ ` The tension force is the force that is transmitted through a string, rope, cable or wire when it is pulled tight by forces acting from opposite ends.
`color{red}✍️ ` The tension force is directed along the length of the wire and pulls equally on the objects on the opposite ends of the wire.
`color{red}✍️ ` For an inextensible string, the force constant is very high.
`\color{fuchsia} {★ \mathbf\ul"Spring Force"}`
`color{red}✍️ ` When a spring is compressed or extended by an external force, a restoring force is generated.
`color{red}✍️ ` This force is usually proportional to the compression or elongation (for small displacements). The spring force `F` is written as `F = – k x` where `x` is the displacement and `k` is the force constant.
`color{red}✍️ ` The negative sign denotes that the force is opposite to the displacement from the unstretched state.