Question

1. why does a sand dune form when wind blows sand against an obstacle? a) the sands kinetic energy is destroyed. b) the sands kinetic energy is transformed into thermal energy by friction. c) the wind creates energy from nothing. d) the sand does not lose any energy.

Explanation:

Energy cannot be created or destroyed according to the law of conservation of energy. When wind - blown sand hits an obstacle, its kinetic energy is transformed. Option a is incorrect as energy is not destroyed. Option c violates the conservation of energy principle. Option d is incorrect because the sand does lose kinetic energy. When the sand hits the obstacle, friction causes its kinetic energy to be transformed into thermal energy.

Answer:

b) The sand's kinetic energy is transformed into thermal energy by friction.