Stretching Notes PDF

# Stretching ## Mass vs Weight: - Mass is how much matter something is made of. - Mass is measured with a balance or scales in kg/g and doesn't change in different locations. - Weight is the force gravity pulls on an object to the centre of the Earth. - It is measured with a newtonmeter with newto...

# Stretching ## Mass vs Weight: - Mass is how much matter something is made of. - Mass is measured with a balance or scales in kg/g and doesn't change in different locations. - Weight is the force gravity pulls on an object to the centre of the Earth. - It is measured with a newtonmeter with newtons (n) and changes in different locations. - Weight is calculated with: - Weight = Mass x Gravitational field strength or W=MG - On Earth, the gravitational field strength (g) is 10m/s² (meters per second squared) - This means if something fell on Earth, it would fall faster by 10 meters every second. ## Stretching: - An elastically-behaving object returns to its original shape when the force is removed. - A plastically - behaving object deforms and stays the same shape when force is removed. - The elastic limit is the point of permanent deformation (when an object starts behaving plastically). ### Objects behaving elastically: - spring - elastic band - Scrunchy - jumper ### Objects behaving plastically: - chewing gum - bluetac - slime - Plasticine ## Hooke's Law: - Hooke's Law says that the extension of a spring is directly proportional to the force applied, without exceeding the elastic limit. - This means if three times as much force is added onto the spring, it will extend twice as much, up to the elastic limit. - It increases by an equal amount each time. - A spring's stiffness is how much force it takes to extend it by a certain amount. - Hooke's Law has an equation: - F= ke **always write lowercase** - Force = Spring constant x Extension ## Combining Springs: ### Springs in Series: - When identical springs are connected one after the other, each spring will feel the same force and would stretch by the same amount. - Total extension = stretch of 1 spring x number of springs. ### Springs in parallel: - When identical springs are connected next to each other, the spring shares the force and stretch by a fraction of the extension. - Total extension = extension of 1 spring + number of Springs. ## Graphs: - Label axes - Equal scale - Line of best fit should be straight. - Plot with pencil ### Gradient: - The gradient is the spring constant. - The gradient is the slope of a line depending on the vertical movement of each unit. ### *Practice* - To find the gradient, divide height by the length. - Eg: 3-1=3 - gradient = 3 **Diagram of three springs in series connected to a mass on one end, and the connection point on the other end to a fixed point.** **Diagram of three springs in parallel connected to a mass on one end, and the connection point on the other end to a fixed point.** **Diagram of a graph with Force (N) on the y-axis and Extension (m) on the x-axis.**