B) A man is cutting down a tree with an axe. He hears the echo of the impact of the axe hitting the tree after 1.8 s.
i. What sort of obstacle could have caused the echo? [1]
ii. The speed of sound is 330 m/s. How far is the tree from the obstacle? [3]
c) Distinguish between the nature of sound waves in b and the water wave in a.

in physics zero. in muscle fatigue could be high

which piece of furniture will have the most inertia and give the furniture movers the most difficulty in moving?  

answer

a 75kg dining table

the order for strong to weak forces such as

strong nuclear force → electromegnetic force → weak nuclear force → gravitational force

the fundamental forces are those forces that act between to objects or element to make interactions. there are four types of fundamental forces such as strong and weak nuclear forces (due to protons and electrons), electromagnetic force (due to the motion of electrons) and gravitational force (due to orbital movement of the planet). if these forces are arranged on the basis of their maximum strength then the order is

strong nuclear force → electromegnetic force → weak nuclear force → gravitational force