Answer:

Explanation:
we know that



as we see that 
relative error
Where X_1 IS HEIGHT OF ROCK
IS THE HEIGHT OF ROAD
= uncertainity in measuring distance

Putting all value to get uncertainity in angle

solving for
we get

Answer:
the velocity is zero, the acceleration is directed downward, and the force of gravity acting on the ball is directed downward
Explanation:
Is this exercise in kinematics
v = v₀ - g t
where g is the acceleration of the ball, which is created by the attraction of the ball to the Earth.
At the highest point
velocity must be zero.
The acceleration depends on the Earth therefore it is constant at this point and with a downward direction.
The force of the earth on the ball is towards the center of the Earth, that is, down
all other alternatives are wrong
Answer:
Matter is anything that has mass
Explanation:
The word "matter" refers to anything that has mass, either organic or inorganic. Matter is made up of atoms, which consists of a nucleus (made up of protons, positively charged, and neutrons, electrically neutron) and electrons which revolve around the nucleus.
The number of protons in the atom determine the element: there are more than 100 different elements in nature, with different properties depending on the number of electrons they have.
Matter can be in three different states also:
- solid: the atoms are tightly bond to each other, so they cannot move
- liquids: atoms are not bond to each other, so they can slide past each other, but still they have some intermolecular forces that keep them close to each other
- gas: atoms are free to move, as there are no forces that keep them close to each other