Answer:
a) It is moving at
when reaches the ground.
b) It is moving at
when reaches the ground.
Explanation:
Work energy theorem states that the total work on a body is equal its change in kinetic energy, this is:
(1)
with W the total work, Ki the initial kinetic energy and Kf the final kinetic energy. Kinetic energy is defined as:
(2)
with m the mass and v the velocity.
Using (2) on (1):
(3)
In both cases the total work while the objects are in the air is the work gravity field does on them. Work is force times the displacement, so in our case is weight (w=mg) of the object times displacement (d):
(4)
Using (4) on (3):
(5)
That's the equation we're going to use on a) and b).
a) Because the branch started form rest initial velocity (vi) is equal zero, using this and solving (5) for final velocity:


b) In this case the final velocity of the boulder is instantly zero when it reaches its maximum height, another important thing to note is that in this case work is negative because weight is opposing boulder movement, so we should use -mgd:

Solving for initial velocity (when the boulder left the volcano):


Answer:
243 N
Explanation:
The formula for electromagnetic force is F= Kq1q2/r^2
where r is the distance between the charges, if the distance between the charges is reduced by 1/3 then F will increase by 9 [(1/3r)^2 becomes 1/9r which is 9F] so 27*9 is 243N
Answer:
D. The General Adaptation Syndrome
Explanation:
Hans Selye, an endocrinologist, developed the <em>"Stress Theory."</em> He showed the relationship of <em>"stress"</em> to the person's development of disease.
Under stress, <em>a person's body experiences changes</em>. The person tries to cope with these through three stages: <em>Alarm Reaction Stage, Resistance Stage and Exhaustion Stage. </em>It is at the<em> last stage</em> that a person's immune system is placed at a huge risk. Once the person is exposed to a stressor for a period of time, he becomes hopeless and his body tends to give up coping. He then succumbs to <em>stress-related illness.</em>
Answer:
15.01 Liters
Explanation:
T₁ = Initial temperature = 25°C = 298.15 K
T₂ = Final temperature = 100°C = 373.15 K
V₁ = Initial volume = 12 mL
Here, pressure is constant so we apply Charles Law

∴ Final volume at 100°C is 15.01 Liters.