Work, Energy an...

Assertion If two protons are brought near one another, the potential energy of the system will increase.
Reason The charge on the proton is +1.6 × 10^–19 C.

Assertion Mass and energy are not conserved separately, but are conserved as a single entity called mass-energy.
Reason Mass and energy conservation can be obtained by Einstein equation for energy.

Assertion Mass and energy are not conserved separately, but are conserved as a single entity called mass-energy.
Reason Mass and energy conservation can be obtained by Einstein equation for energy.

Assertion When a gas is allowed to expand, work done by gas is positive.
Reason Force due to gaseous pressure and displacement (of piston) are in the same direction.

Assertion A light body and heavy body have same momentum. Then they also have same kinetic energy.
Reason Kinetic energy does not depend on mass of the body.

Assertion Mountain roads rarely go straight up the slope.
Reason Slope of mountains are large therefore more chances of vehicle to slip from roads.

Assertion A spring has potential energy, both when it is compressed or stretched.
Reason In compressing or stretching, work is done on the spring against the restoring force.

Assertion Comets move around the sun in elliptical orbits. The gravitational force on the comet due to sun is not normal to the comet\'s velocity but the work done by the gravitational force over every complete orbit of the comet is zero.
Reason Gravitational force is a non conservative force.

Assertion The rate of change of total momentum of a many particle system is proportional to the sum of the internal forces of the system.
Reason Internal forces can change the kinetic energy but not the momentum of the system.

Assertion Work done in moving a body over a closed loop is zero for every force in nature.
Reason Work done does not depend on nature of force.