In Physics, force and energy are the most important concepts that students learn in their high school. Force is mass multiplied by acceleration. Energy is Force multiplied by distance. Today, we are going to focus on different types of forces and energy.
Force is mass times acceleration. If a car with a mass of 1000kg accelerates at 3m/s^2, the force being applied to the car is 3 x 1000 = 3000N. However, is this all type of force?
There is force applied to us by the gravity. We are accelerating at 9.81m/s^2 downward right now. The reason why we are not moving is because of the ground holding us up. So the force applied to us right now would be our mass times 9.81m/s^2.
Also there is force of spring. There is a spring constant, k. The force applied to an objected attached to a spring is length of the stretched string minus length of the string at equilibrium, and then multiply it by its spring constant. So if a spring A has a spring constant of 3N/m, and the spring is stretched 5m, then the force of 15N is being applied to the spring.
Energy is a force times a distance. If one applies 5N of force to a block and the block moves 2m, then 5×2=10J of energy has been used doing the work.
There are also potential energy and kinetic energy. Potential energy is mass times gravity acceleration times height. Kinetic energy is 0.5 times mass times velocity times velocity.
PE = mgh, m=mass, g=gravity acceleration, h=height
KE=0.5mv^2, m=mass, v=velocity
The energy is conserved at all times. Therefore if you drop a ball from a slide with height of 3m, then the kinetic energy in the bottom would be equal to the potential energy the ball has in the top.
Also there is another energy with spring.
Spring energy is 0.5 times spring constant times distance times distance.
SE=0.5kx^2, k=spring constant, x=distance.
It is same for the spring, the energy is conserved. IF a spring constant of a spring is 1, and it is stretched by 2. Then it would have energy of 1J.
Assume the object hanging from the spring is 0.5kg. If the spring is released, the kinetic energy of the object would be 1J. so its velocity should be 2m/s.
0.5 x 0.5 x 2^2 = 1J
The kinetic energy of the object would still be 1J.
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