A valid hypothesis must have test for proving the observation and is realistic, it considers the varibales it wants to measure. And it is tested either finding significance or not in the relationship between the studied variables.
<span>They utilize and make use of the scientific method in order to have clear basis and evidence for their investigations. Research method is always used to answer every scientific inquiry and in gaining evidential data or knowledge. The scientific method has the following process or at least undergoes the process of
1. Observation</span>
2. Hypothesis
3. Experimentation
4. Interpretation of data
5. Evaluating the data
6. Passing and recording the data
<span>These steps are crucial and the empirical data that these scientists obtain are very important to keep that is why research paper, thesis and dissertations exists.<span>
</span></span>
Answer:
approximately 30 degrees
Explanation:
If it takes the cannonball 2 seconds to reach the maximum height, we can use the analysis of the vertical component of the velocity and the fact that the acceleration of gravity is the one acting opposite to this initial vertical component 
of the velocity. We know as well that at the top of the trajectory, the vertical component of the velocity is zero, and then the movement starts going down in it trajectory. So, the final velocity for the first part of the ascending movement is zero, giving us the following equation for the velocity under an accelerated movement (with acceleration of gravity "g" acting):
By knowing the vertical component of the initial velocity (19.6 m/s), and the actual magnitude of the total initial velocity (40 m/s), we can calculate what angle was the initial velocity vector forming above the horizontal. We use for such the fact that the sine of the angle relates the opposite side of a right angle triangle with the hypotenuse, and solve for the angle using the arcsin function:
which tells us that the closer answer shown is 
Answer:
3 * 10³J/s
Explanation:
Given :
Force applied, F = 300 N
Distance, d = 30 m
Time, t = 3 seconds
Power, P = Workdone / time
Recall :
Workdone = Force * distance
Workdone = 300 N * 30 m = 9000 Nm
Workdone = 9 * 10³ J
Power = (9 * 10³ J) / 3s
Power = 3 * 10³J/s
Answer:
because the gravity of the earth
