What type of energy is stored in the spring of a watch?

Justify,giving proper reasoning,whether the work done in the following case is positive or negative: Work done by an applied force on a body moving on a rough horizontal plane with uniform velocity.

Seema tried to push a heavy rock of $100 \, kg$ for $200 \, s$ but could not move it. Find the work done by Seema at the end of $200 \, s$. (in $, J$)

Define $1\, W$ of power. $A$ lamp consumes $1000\, J$ of electrical energy in $10\, s$. Calculate its power.

When a ball is thrown vertically upwards,its velocity goes on decreasing. What happens to its potential energy as its velocity becomes zero?

$A$ mass of $10 \, kg$ is dropped from a height of $50 \, cm$. Find its:
$(a)$ Potential energy just before dropping.
$(b)$ Kinetic energy just on touching the ground.
$(c)$ Velocity with which it hits the ground. (Given: $g = 10 \, m s^{-2}$)