All of the above as it states that "<span>a particle attracts every other particle in the universe using a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between their centers"</span>
This is a list of well known characteristics of acids:
1) acids increase the concentration of hydronum ions ([H3O+]) when dissolved in water
2) acids taste sour
3) many are corrosive (the higher the acidity the higher the corrosive property)
4) when acids react with some metals produce hydrogen gas
5) acids conduct electricity (due to the presence of hydronium ions)
6) acids neutralize bases
7) acids combine with bases to produce water and salt
8) acids lower the pH of solutions.
They do not feel sticky to the touch. Bases fell slippery but there is not that property of sticky sensation about acids, although some highly concentrated strong acids have high viscosity. You cannot touch highly concentrated strong acids.
Explanation:
Given that,
A person walks 9.0 km directly east and then turns left and heads directly north for 12.0 km.
We need to find his displacement from the starting position.
We know that,
Displacement = shortest path covered

For direction,

Hence, this is the required solution.