Tag: concept of energy

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Questions Related to concept of energy

Multiple choice physics energy : forms and sources concept of energy energy for everything forms of energy

If the values of force and length are increased four times then the unit of energy will increases by?

  1. $4$ times
  2. $2$ times
  3. $8$ times
  4. $16$ times
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

 Force is represented as $\left[ ML{ T }^{ -2 } \right] \quad and\quad length\left[ L \right] $

$energy\quad f\times d\quad is\left[ ML{ T }^{ -2 } \right] \quad \times \left[ L \right] =\left[ M{ L }^{ 2 }{ T }^{ -2 } \right] $
 if Force and length are quadrupled in value Energy
$4\left[ ML{ T }^{ -2 } \right] \quad \times 4\left[ L \right] =16\left[ M{ L }^{ 2 }{ T }^{ -2 } \right] $
unit increased by 16 times 

Multiple choice physics work, energy and machines concept of energy energy for everything forms of energy

When a men walks on a horizontal surface  then work done by

  1. friciton is zero

  2. contact force is non-zero

  3. gravity is non-zero

  4. None of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

When the man moves on a horizontal surface, then work done by gravity is zero since gravitational force acts perpendicular to the displacement. 


And the normal force will be also perpendicular to displacement so work done by It also is zero. - - - - - - - - 1

But frictional force is acting opposite to displacement so work done by frictional force is negative. - - - - - - - - - - - 2

Using statement (1) and (2) we can say that work done by contact force is non - zero 


Multiple choice physics simple machines concept of energy energy for everything forms of energy

Energy can be defined as:

  1. The capacity to do work

  2. Work done in unit time

  3. A push or a pull

  4. Attraction between two oppositely charged particles
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Energy is the capacity of a physical system to perform work. Energy exists in several forms such as heat, kinetic or mechanical energy, light, potential energy, electrical, or other forms.