Select True or False for each statement. 1. Without friction or work by an exter
ID: 1463111 • Letter: S
Question
Select True or False for each statement. 1. Without friction or work by an external force, the sum of the potential and kinetic energies of a body is constant. 2. Work is done when the form of energy changes. 3. Energy conservation law for a projectile (no friction): Potential energy increase equals the kinetic energy decrease. 4. Work can be done in the absence of motion. 5. Less power is required while lifting a box up quickly than while slowly lifting it. 6. A source of energy is required to do work.
Explanation / Answer
1. Without friction or work by an external force, the sum of the potential and kinetic energies of a body is constant.
True
because without an external force energy of a system remain conserve
2. Work is done when the form of energy changes
True
As work done on the system changes the energy of the system
3. Energy conservation law for a projectile (no friction): Potential energy increase equals the kinetic energy decrease.
True
4. Work can be done in the absence of motion
False ( this is false in case of mechanics)
5. Less power is required while lifting a box up quickly than while slowly lifting it
False
6. A source of energy is required to do work.
True