Given that,
Mass of the stone, m = 400 g = 0.4 kg
Initial speed, u = 20 m/s
It is climbed to a height of 12 m.
To find,
The work done by the resistance force.
Solution,
Let v is the final speed. It can be calculated by using the conservation of energy.

Work done is equal to the change in kinetic energy. It can be given as follows :

So, the required work done is 32.99 J.
The bar magnet and the electromagnet act identical. The difference being a electromagnet is a coil of wire that has a power source connect to both ends, this energizes the coil with an electromagnetic field.
Answer:
Option D is the correct answer.
Explanation:
Stress is the force per unit area that tend to change the shape of body.
Stress is defined as internal resistive force per unit area.


So, so stress distributed over an area is best described as internal resistive force.
Option D is the correct answer.
These two forces are called action and reaction forces and are the subject of Newton's third law of motion.
<em>Have a luvely day!</em>