Question

What is energy? What is unit of energy?

August 4, 2024

Answer

The capacity of a body to do work is called energy possessed by the body. Itis a scalar quantity and is measured in joule (J).

Generally, for practical purposes, a bigger unit called kilojoule (kJ) is used (1 kJ = 1000 J).

💡 Some Related Questions

The diagram below shows a pendulum which was released from position A. (a) What form(s) of energy did the pendulum have at (i) A? (ii) B? (iii) C? (b) Eventually the pendulum would stop moving. Explain what has happened to the initial energy of the pendulum.

Is it possible that an object is in the state of accelerated motion due to external force acting on it, but no work is being done by the force? Explain with example.

Can any object have momentum even if its mechanical energy is zero? Explain

Can any object have mechanical energy even if its momentum is zero? Explain.

Anil lives in a village and his school is 8 km away from his home. His father suggests buying a motor cycle to go to school. Anil opposes the idea and opts for a bicycle instead. (𝒊) Write the energy transformation taking place while Anil rides his bicycle. (𝒊𝒊) Justify the stand taken by Anil in your own words. (𝒊𝒊𝒊) How can he convince his friends to do the same?

Shyam and his friends were playing with a catapult (gulel) in his garden. Several mangoes were dislodged and fell with the help of catapult. One of his friend was aiming the catapult on a bird. Shyam prevented him from doing so. (𝒊) Name the energy possessed by the stretched string of the catapult. (𝒊𝒊) What will happen if the stone is thrown without stretching the string of a catapult? (𝒊𝒊𝒊) Why did Shyam prevent his friend from aiming at the bird? Which quality is highlighted in Shyam’s behavior?

Prachi and Kanchi were observing a building having two different staircase. One slanting and other vertically spiral. Prachi was of the opinion that a person using slanting staircase will be doing more work against gravity but Kanchi thought otherwise. They started arguing. Sanchi, their friend, explained and gave entirely different view and pacified them. (𝒊) What according to you was the explanation given by Sanchi? (𝒊𝒊) What appreciable values do you see in Sanchi?

Ram’s family was worried about heavy electricity bills to be paid. Their neighbour Mohan suggested some easy and effective steps to reduce the same. Next month’s bill came as a relief to Ram, as the consumption of electricity had reduced by 50 units and so had the bill. (𝒊) In what other aspects of life can this situation help? (𝒊𝒊) What is the unit of energy? (𝒊𝒊𝒊) Write any three steps that you think Mohan might have suggested to Ram.

On a railway station, a passenger hires a coolie to pick his luggage and carry it to the train. When the coolie finished his work, he asked for the money. But the passenger refused to pay him saying that he has done no work. Answer the following questions based on the above information: (𝒊) Was the passenger right in saying so? (𝒊𝒊) What values are not promoted by the passenger? (𝒊𝒊𝒊) Give a situation seen in everyday life when no work is said to be done by you even though you get tired.

Figure shows a conveyor belt transporting a package to a raised platform. The belt is driven by a motor. (𝒊) State three types of energy, other than gravitational potential energy, into which the electrical energy supplied to the motor is converted. (𝒊𝒊) The mass of the package is 36 kg. Calculate the increase in the gravitational potential energy (P.E.) of the package when it is raised through a vertical height of 2.4 m. (𝒊𝒊𝒊) The package is raised through the vertical height of 2.4 m in 4.4 s. Calculate the power needed to raise the package. (𝒊𝒗) Assume that the power available to raise package is constant. A package of mass greater than 36 kg is raised through the same height. Suggest and explain the effect of this increase in mass on the operation of the belt.