According to the formula

Where a is work, f is force and d is the distance that box was moved over. And from that formula, you can get that f = a/d and that is 54.83N of force
(G)-->Iron and steel industry is called a heavy industry because all the raw material as well as finished goods are heavy and bulky entailing heavy transportation costs. Iron ore, coking coal and limestone are required in the ratio of 4:2:1 approximately. Some quantity of manganese is also required to harden the steel.
(H)-->Sodium is very reactive in nature. When exposed in air, it automatically forms Na2O. When it is put in water it reacts vigorously and starts burning on water. Due to the above reasons Sodium is called an active metal.
(I)-->Down the group, the effective nuclear charge experienced by valence electrons is decreasing because the outermost electrons are far away from the nucleus. Thus, these electrons can be lost easily by the element to form positive ions. Hence, the chemical reactivity of metals increases on going down a group.
(J)-->While moving from top to bottom in a group of the periodic table, the reactivity of non- metals decreases. While moving from top to bottom in a group of non- metals, the atomic size increases with the additional number of shells and the force of attraction between the nucleus and valence shell decreases.
Yes, think about the difference of swinging a bat and not hitting a ball. It's fairly easy right? Now, when you hit a ball with the bat, you will feel the bat sting your hands. That's the force the ball is exerting on the bat!
Answer:v=3.28 m/s
Explanation:
Given
mass of rock 
diameter of circle 
radius 
At highest Point

At highest Point N=0 because mass is just balanced by centripetal Force
thus 



