Answer:
<u>A</u>
Explanation:
The heart cells must contract simultaneously to move blood.
This means that it needs to act fast and efficiently.
Therefore, the connections among heart cells are characterized by :
- having many branches
- having many communicating junctions
The correct option should be <u>A</u>
Answer:
Explanation:
Rocks tell us a great deal about the Earth's history. Igneous rocks tell of past volcanic episodes and can also be used to age-date certain periods in the past. Sedimentary rocks often record past depositional environments (e.g deep ocean, shallow shelf, fluvial) and usually contain the most fossils from past ages.
Answer:
14.8m
Explanation:
Given parameters:
Initial speed = 17m/s
Unknown:
Maximum height = ?
Solution:
At the maximum height, the final speed will be 0m/s;
We use of the kinematics equation to solve this problem.
V² = U² - 2gH
V is the final velocity
U is the initial velocity
g is the acceleration due to gravity
H is the height
0² = 17² - (2 x 9.8 x h )
0 = 289 - (9.6h)
-289 = -19.6h
h = 14.8m
Answer:
when we lower a bucket into a well to fetch water, the work done by gravity is positive since force and displacement are in the same direction.
Explanation:
Answer:
Explained below
Explanation:
Newton's first law of motion: This law states that an object will remain at rest or continue in constant motion except it's acted upon by an external force. In projectile motion, the horizontal component of velocity will remain unchanged because we ignore air resistance since no force is acting in that horizontal direction.
Newton's second law of motion: This law states that force is the product of mass and acceleration. In projectile the force acts downwards, thus f = mg.
But g = a since internal forces will cancel out.
Thus, F = ma
