Select True or False for each statement. 1 Less power is required while slowly l
ID: 1260531 • Letter: S
Question
Select True or False for each statement.
1 Less power is required while slowly lifting a box than while lifting it up quickly.
2 A source of energy is required to do work.
3Energy conservation law for a projectile (no friction): Potential energy decrease equals the kinetic energy increase. 4Work cannot be done in the absence of motion.
5Without friction or work by an external force, the sum of the potential and kinetic energies of a body is constant.
6Work is done when the form of energy changes.
Explanation / Answer
1.True, P = W/t, low power means more time and vice versa.
2. False, objects can do work from gravity
3.True, the change in kinetic energy equals the change in potential energy (in perfect situations).
4.False, W = Fd, which means if d is 0, W is 0.
5. TRUE Without friction or work by an external force, the sum of the potential and kinetic energies of a body is constant.
6.True, when potential goes to kinetic, work is done.