Solution :
Acceleration due to gravity of the earth, g
Acceleration due to gravity at 1000 km depths is :
= 8.23 m/s
Acceleration due to gravity at 2000 km depths is :
= 6.73 m/s
Acceleration due to gravity at 3000 km depths is :
= 5.18 m/s
Acceleration due to gravity at 4000 km depths is :
= 3.64 m/s
Balanced Forces acting on an object will not change the object's motion. Unbalanced Forces acting on an object will change the change the object's motion.
I would say Option B) because Option C) is wrong since matter cannot be created. A closed system does not exchange matter so it's not Option D). Since an island is an isolated area, Option A) is wrong.
The ice and how the blades are made
Similar elements with similar properties were in the same groups and periods for instance lithium(Li) and sodium(Na) are alkaline metals and so belong to the same group (that is group 1).Also Hydrogen(H) and Helium(He) both have only one shell or energy level and so belong to the same period.