Advertisements
Advertisements
Question
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)
Options
6 ×103 J
6 J
0.6 J
zero
Advertisements
Solution
zero
Explanation:
The gravitational force on the bag, i.e. the weight of the bag is in a vertically downward direction whereas the distance moved by her is in the horizontal direction. It means that the force and displacement are perpendicular to each other, therefore no work is done.
APPEARS IN
RELATED QUESTIONS
State the condition under which the mechanical energy is conserved.
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 :
Chemical energy into electrical energy.
Name the device or machine which convert :
Chemical energy into kinetic energy (or mechanical energy).
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?
Explain the transformation of energy in the following cases :
(i) A ball thrown upwards.
(ii) A stone dropped from the roof of a building.
Name the energy transfers which occur when someone speaks into a microphone.
When an object falls freely towards the earth, then its total energy :
In the case of negative work, the angle between the force and displacement is
