Answer:
A force
Explanation:
A push or a pull is an example of a force and can cause an object to speed up, slow down, etc.. Newton's laws tell us that 1- an object will not change its motion unless a force acts on it 2- the force on an object is equal to its mass times its acceleration. 3- The third law states that for every action (force) in nature there is an equal and opposite reaction.. However, forces like gravity and friction can resist movement.
Density can be any number, as long as it has the right units.
A unit of density has to be (a unit of mass) divided by (a unit of volume).
The most common one is gram/cm^3.
Answer:
19.2*10^6 s
Explanation:
The equation for time dilation is:

Then, if it is observed to have a life of 6*10^6 s, and it travels at 0.95 c:

It has a lifetime of 19.2*10^6 s when observed from a frame of reference in which the particle is at rest.
Answer:
B
Explanation:
Water level remains unchanged
The first thing to realize is that the buoyancy force is the same as, or equal to the weight of the wood, this same force is also the same as or equal to the weight of the water displaced by the wood. In the two cases, the weight of the wood will be unaffected nonetheless, and thus the water level will remain the same.
Therefore, the answer is B, the water level remains unchanged.