Answer: 60mph
Explanation:
Given the following :
First leg travel:
Distance = 30 miles
Time of travel= 30 minutes = 0.5 hour
Second leg travel:
Distance = 60 miles
Time of travel = one hour
Average speed :
Speed = total Distance / time of travel
Total distance in miles = (30 + 60) miles = 90 miles
Total time of travel = 1 hour + 0.5 hour = 1.5 hours
Average speed = total distance traveled / total travel time
Average speed = 90 miles / 1.5 hours
Average speed = 60 miles / hour
= 60mph
Answer:
Natural selection is a simple mechanism that causes populations of living things to change over time. Organisms that are more adapted to their environment are more likely to survive and pass on the genes that aided their success.
Answer:
A: The acceleration is 7.7 m/s up the inclined plane.
B: It will take the block 0.36 seconds to move 0.5 meters up along the inclined plane
Explanation:
Let us work with variables and set

As shown in the attached free body diagram, we choose our coordinates such that the x-axis is parallel to the inclined plane and the y-axis is perpendicular. We do this because it greatly simplifies our calculations.
Part A:
From the free body diagram we see that the total force along the x-axis is:

Now the force of friction is
where
is the normal force and from the diagram it is 
Thus
Therefore,

Substituting the value for
we get:

Now acceleration is simply

The negative sign indicates that the acceleration is directed up the incline.
Part B:

Which can be rearranged to solve for t:

Substitute the value of
and
and we get:
which is our answer.
Notice that in using the formula to calculate time we used the positive value of
, because for this formula absolute value is needed.
Answer and Explanation:
The hydrogen atom is an atom of hydrogen element.Hydrogen atoms contain one proton which has positive charge and one electron which has negative charge , so due to positive and negative charge present in the hydrogen atom its becomes neutral atom.In whole universe the hydrogen atom is found in most abundant. Electron and nucleus of the hydrogen atom is bound together with the help of coulomb force.