Explanation:
A molecule can be made up from same or different elements. Whereas a compound will have different atoms.
Therefore, the difference between a molecule and a compound is that a compound is made up of atoms from different elements.
For example,
is a molecule and NaCl is a compound.
And a chemical change creates a new substance.
Answer:
Therefore it is save to carry a 62kg adult
Explanation:
From the question we are told that:
Mass 
Height of supporting Rock 
Length of Board
Mass of board 
Mass of adult
Generally the moment of balance about wedge part about is mathematically given by



where

therefore

if N=0 at fallen person

Therefore it is save to carry a 62kg adult
3 protons should be your answer
Answer:2.6 h
Explanation:
Given
Total Trip distance=450 miles
Meeting starts after 10.8 hours
safe Fastest speed is 55 mi/h
so if he drives all the to the meeting with max speed then it takes 
and total allowable time is 10.8
Therefore longest time he can spend over dinner is 