Umamahadev
Illustrate the law of conservation of energy by discussing the energy changes which occur when we draw a pendulum bob to one side and allow it to oscillate. Why does the bob eventually come to rest? What happens to its energy eventually? Is it a violation of the law of conservation of energy?
A pendulum is a object is hang to a fixed position with thread that do back and forth motion. (left and Right) When bob is on maximum right side ( At Rest ) Since Bob is at some height and at rest not released, so it has stored potential Energy but zero kinetic Energy.Let’s suppose … Read more
A person holds a bundle of hay over his head for 30 minutes and gets tired. Has he done some work or not? Justify your answer.
When a person holds a bundle of hay over his head, it means it apply his muscular force to hold the hay but he doesn’t do any displacement, since force is applied but there is no displacement. Since No work is Done.
Can there be displacement of an object in the absence of any force acting on it? Think. Discuss this question with your friends and teacher.
Here , we know that Force = Mass * Acceleration When force is 0 , it means Acceleration is also 0. When acceleration is Zero, It means body is moving in uniform motion, since it has speed so it can obviously doing a displacement of an object. Yes , we can say that there be … Read more
What is the work done by the force of gravity on a satellite moving round the earth? Justify your answer.
Here, When satellite is moving around the earth, the Gravitational force experienced to the satellite along the center of the earth. ( Radius of the Earth ) But the Satellite is moving in circular path along the tangent of the circle. Since displacement is along the tangent. We know the tangent of the circle is … Read more
An object of mass 40 kg is raised to a height of 5 m above the ground. What is its potential energy? If the object is allowed to fall, find its kinetic energy when it is half-way down.
Here , Mass = 40 kg Height = 5 m g ( force of gravity ) = 10m/sĀ² Potential Energy = Mgh = 40*10*5 = 2000 Joule ( j ) Now Second part when object is at half way down then it gain some velocity now to calculate velocity we have to apply motions of … Read more
A certain Household has consumed 250 units of energy during a month. How much energy is this in Joules?
The energy measured in household in Kilo watt hour. We know that 1 Unit is equal to 1kWH 1 unit = 1 kwh Now, 1 kWh = 3.6 Ć 10ā¶ joules 250 KWH = 250 Ć (3.6 Ć 10ā¶) = 9.0 Ć 10āø joules SO, 250 units = 250 KWH = 9.0 Ć 10āø joules … Read more
Does the transfer of energy take place when you push a huge rock with all your might and fail to move it? Where is the energy you spend going?
The Rock has huge mass, so friction force is also huge so when we tried to move the rock, our force is much smaller than friction force. According to law of conservation of energy , energy neither created not destroy it can only change to one form to other. so our energy get converted in … Read more
What are the various energy transformations that occur when you are riding a bicycle?
When we are riding a bicycle, we use our muscular energy to move the bicycle and also our body will warm up during riding bicycle. Hence we can say that muscular energy get converted in to kinetic energy and heat energy. Energy Transformation –> Muscular Energy –> ( kinetic Energy + Heat Energy )
The potential energy of a freely falling object decreases progressively. Does this violate the law of conservation of energy? Why?
when an object goes to freely falling at some height (h) is has stored potential energy equal to mgh. Then start falling, its height decreases but speed increases so as height decreased we say that potential energy decreased as ( h ) decreased so mgh decreases but on the other hand velocity increases (v) so … Read more