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प्रश्न
Fill in the blank with suitable word :
The sum of the potential and kinetic energies of a body is called __________ energy.
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उत्तर
The sum of the potential and kinetic energies of a body is called mechanical energy.
संबंधित प्रश्न
In what way does the temperature of water at the bottom of a waterfall differ from the temperature at the top? Explain the reason.
State the condition under which the mechanical energy is conserved.
Show that the sum of kinetic energy and potential energy (i.e., total mechanical energy) is always conserved in the case of a freely falling body under gravity (with air resistance neglected) from a height h by finding it when
- The body is at the top.
- the body has fallen a distance x.
- the body has reached the ground.
A stone of mass 500 g is thrown vertically upwards with a velocity of 15 m/s. Calculate:
- the potential energy at the greatest height,
- the kinetic energy on reaching the ground, and
- the total energy at its half-way point.
State whether the object possess kinetic energy, potential energy, or both :
A flying aeroplane _______________.
A boy weighing 40 kg makes a high jump of 1.5 m.
What is his kinetic energy at the highest point?
Give two examples where a body possesses both, kinetic energy as well as potential energy.
Two bodies having equal masses are moving with uniform speeds of v and 2v respectively. Find the ratio of their kinetic energies.
A ball of mass 0.5 kg slows down from a speed of 5 m/s so that of 3 m/s. Calculate the change in kinetic energy of the ball. State your answer giving proper units.
Name the device or machine which convert :
Light energy into electrical energy.
How much electrical energy in joules does a 100 watt lamp consume : in 1 minute?
Describe the energy changes which take place in a radio.
Write the energy transformations which take place in an electric bulb (or electric lamp).
The hanging bob of a simple pendulum is displaced to one extreme position B and then released. It swings towards centre position A and then to the other extreme position C. In which position does the bob have :
(i) maximum potential energy?
(ii) maximum kinetic energy?
Name the energy transfers which occur when an electric ball rings.
Name the energy transfers which occur when there is a picture on a television screen.
A ball falls to the ground as shown below :
What is the kinetic energy of ball when it hits the ground?
The device which converts mechanical energy into energy which runs our microwave oven is :
A girl is carrying a school bag of 3 kg mass on her back and moves 200 m on a levelled road. The work done against the gravitational force will be (g = 10 m s–2)
A girl with having a mass of 35 kg sits on a trolley of mass 5 kg. The trolley is given an initial velocity of 4 m s–1 by applying a force. The trolley comes to rest after traversing a distance of 16 m. (a) How much work is done on the trolley? (b) How much work is done by the girl?
