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प्रश्न
A body of mass 10 kg falls from a height of 20 m to 8 m. Calculate:
- the loss in potential energy of the body, and
- the total energy possessed by the body at any instant? (Take g = 10 m s-2)
उत्तर
(i) Loss in potential energy = P.E at height 20 m – P.E. at height 8 m
= mg 20 – mg 8
= mg (20 – 8)
= mg (12) = 12 mg
= 10 × 10 × 12
= 1200 J
(ii) Say at a height 20 m above ground level
= P.E. + K.E.
= mgh + 0
= 10 × 10 × 20 + 0
= 2000 J
(∵ V = 0 when held at 10 m, Hence K.E. = 0)
संबंधित प्रश्न
A ball of mass 0.20 kg is thrown vertically upwards with an initial velocity of 20 m s-1. Calculate the maximum potential energy it gains as it goes up.
State whether the object possess kinetic energy, potential energy, or both :
A flying aeroplane _______________.
What are the various forms of energy?
Name the device or machine which convert :
Heat energy into kinetic energy (or mechanical energy).
Name the device or machine which convert :
light energy into heat energy.
Fill in the blanks with suitable words:
When a ball is thrown upwards, ___________ energy is transformed into ___________ energy.
How much electrical energy in joules does a 100 watt lamp consume : in 1 minute?
Name the energy transfers which occur when : a torch is on
A ball falls to the ground as shown below :
What is the kinetic energy of ball when it hits the ground?
Which one of the following is not the unit of energy?
