Select True or False for each statement. True False Energy conservation law for
ID: 1459209 • Letter: S
Question
Select True or False for each statement.
True False Energy conservation law for a projectile (no friction): Potential energy decrease equals the kinetic energy increase.
True False More power is required while slowly lifting a box than while lifting it up quickly.
True False Work can be done in the absence of motion.
True False Work is done when the form of energy changes.
True False Without friction or work by an external force, the sum of the potential and kinetic energies of a body is constant.
True False A source of energy is required to do work.
Explanation / Answer
a)
energy conservation law for a projectile (no friction): Potential energy decrease equals the kinetic energy increase
correct option is True,
because, law of conservation of energy total energy is conserved
b)
More power is required while slowly lifting a box than while lifting it up quickly.
correct option is flase,
power, P=W/t
for slowely lifting abox requires the less power for a given energy
c)
Work can be done in the absence of motion.
correct option is false,
W=F.d
here, if d=0 ==> w=0
d)
Work is done when the form of energy changes.
the correct option is true,
because, law of conservation of energy,
e)
Without friction or work by an external force,
the sum of the potential and kinetic energies of a body is constant.
the correct option is true,
because, law of conservation of energy,
f)
A source of energy is required to do work
the correct option is true,
because, law of conservation of energy,