Mechanics - Forces, acceleration, displacement, vectors, motion, momentum, energy of objects and more.Dynamics - Motion - velocity and acceleration, forces and torque.Power is the ratio of work done to used time - or work done per unit time. P = pressure on a surface A, or in a volume (Pa, N/m 2)ĭV = change in volume for acting pressure p (m 3) The work done per revolution (2 π radians) can be calculated asįorce can be exerted by weight or pressure:ĭs = distance moved for acting force, or acting pressure (m) = 1 N/m Work done by Moment and Rotational DisplacementĪ machine shaft acts with moment 300 Nm. The spring constant can be calculated by modifying eq. The spring force is variable - from 0 N to 1 N as indicated in the figure above - and the work done can be calculated as The work done when a spring is compressed or stretched can be expressed asį spring_max= maximum spring force (N, lb f)Ī spring is extended 1 m. The force is zero with no extension or compression and the work is the half the product force x distance and represented by the area as indicated. The work done by a spring force is visualized in the chart above. The force exerted by springs varies with the extension or compression of the spring and can be expressed with Hooke's Law as = 15000 ft lb Work done by a Spring Force The work made by a person of 150 lb climbing a stair of 100 ft can be calculated as = 392 (J, Nm) Example - Work when Climbing Stair - Imperial units The force acting on the brick is the weight and the work can be calculated as The work done can be calculated asĮxample - Work done when lifting a Brick of mass 2 kg a height of 20 m above ground Example - Constant Force and WorkĪ constant force of 20 N is acting a distance of 30 m. The work is the product force x distance and represented by the area as indicated in the chart. The work done by a constant force is visualized in the chart above. The unit of work in SI units is joule (J) which is defined as the amount of work done when a force of 1 Newton acts for distance of 1 m in the direction of the force. S = distance object is moved in direction of force (m, ft) The amount of work done by a constant force can be expressed asį = constant force acting on object (N, lb f) The work done on the spring is actually the work by you and is k*x², and the work done by the spring is 1/2 kx² ( this is the actual energy you transfer to spring ) so this is the work energy produced in the spring.When a body is moved as a result of a force being applied to it - work is done. This is your answer where you have gone wrong. a triangle ( remember area=force time deflection), and in that total work done by the spring is converted into potential energy which is stored in the spring itself while half of the triangle shows the resistive force which is resisting the work done by you in compression and half of the same force is actually energy to regain its shape. Now, consider half of the square area I.e.
force is directly proportional to deflection, where $k$ (stiffness) is constant, it will look like a square, in that at any point you can find the amount of force require to get desired displacement or deflection.
Let the force be $f$ and displacement be $d$, then when you draw a graph according to Hooke law (I.e. Actually the force which you are applying is not constant.
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