The answer is either
b A system in which Newton's Laws are valid
or
c A system in which there are no external forces.
Explanation:
not a, and not d
There are energy changes in a closed system.
A closed system obeys the conservation laws in its physical description.
Answer:
Explanation:
Work = Force times displacement. Therefore,
W = 3150(75.5) so
W = 238000 N*m
Answer:
Nature selects organisms with specific heritable traits to survive and reproduce
Explanation:
The Evolution Theory by natural selection dictates that organisms with specific inherited characteristics have better survival chances in the new environment.
Inheriting positive traits such as resistance to a certain disease will improve the survival chances of the organism to enable it reproduce and pass that gene to the next generation.
Answer:
(a) t = 1.14 s
(b) h = 0.82 m
(c) vf = 7.17 m/s
Explanation:
(b)
Considering the upward motion, we apply the third equation of motion:

where,
g = - 9.8 m/s² (-ve sign for upward motion)
h = max height reached = ?
vf = final speed = 0 m/s
vi = initial speed = 4 m/s
Therefore,

<u>h = 0.82 m</u>
Now, for the time in air during upward motion we use first equation of motion:

(c)
Now we will consider the downward motion and use the third equation of motion:

where,
h = total height = 0.82 m + 1.8 m = 2.62 m
vi = initial speed = 0 m/s
g = 9.8 m/s²
vf = final speed = ?
Therefore,

<u>vf = 7.17 m/s</u>
Now, for the time in air during downward motion we use the first equation of motion:

(a)
Total Time of Flight = t = t₁ + t₂
t = 0.41 s + 0.73 s
<u>t = 1.14 s</u>
Rotational speed of an object around an axis is the numbers of turns of the object divided by time. <span />