Answer:
Archimedes Principle states that "any body completely or partially submerged in water is acted upon by an upthrust force which is equal to the magnitude of Weight of the body."
Answer
(C).
When there is an angle between the two directions, the cosine of the angle must be considered.
Step by step Solution
The work done by a force is defined as the product of the force and the distance traveled in the direction of motion.
The first answer "Only the component of the force perpendicular to the motion is used to calculate the work" is wrong because, the force perpendicular to motion does no work.
The second choice "If the force acts in the same direction as the motion, then no work is done" is wrong because the work in the direction of the force is
.
Fourth answer "A force at a right angle to the motion requires the use of the sine of the angle" is wrong because the
meaning that there is no work done in the direction perpendicular to the motion.
The third answer" When there is an angle between the two directions, the cosine of the angle must be considered." is correct because the work is calculated using the force in the direction of the motion. The magnitude of this force is 
The answer is C.
Ionic compounds are those that bring together anions and cations bonded together by ionic bonds. The electrostatic forces of the different charges are significant in the bonds that make them strong hence require high energy to break them (high melting point). Due to the regular structure of ionic compound that tend to form lattices in solid form, when struck, they shatter along the lines of weakness of the lattice.