Answer:
4.8 m/s
Explanation:
When she catches the train,
- They will have travelled the same distance.and
- Their speeds will be equal
The formula for the distance covered by the train is
d = ½at² = ½ × 0.40t² = 0.20t²
The passenger starts running at a constant speed 6 s later, so her formula is
d = v(t - 6.0)
The passenger and the train will have covered the same distance when she has caught it, so
(1) 0.20t² = v(t - 6.0)
The speed of the train is
v = at = 0.40t
The speed of the passenger is v.
(2) 0.40t = v
Substitute (2) into (1)
0.20t² = 0.40t(t - 6.0) = 0.40t² - 2.4 t
Subtract 0.20t² from each side
0.20t² - 2.4t = 0
Factor the quadratic
t(0.20t - 2.4) = 0
Apply the zero-product rule
t =0 0.20t - 2.4 = 0
0.20t = 2.4
(3) t = 12
We reject t = 0 s.
Substitute (3) into (2)
0.40 × 12 = v
v = 4.8 m/s
The slowest constant speed at which she can run and catch the train is 4.8 m/s.
A plot of distance vs time shows that she will catch the train 6 s after starting. Both she and the train will have travelled 28.8 m. Her average speed is 28.8 m/6 s = 4.8 m/s.
The latent heat of vaporization for water is
2257 KJ per Kg . I'm pretty sure that's exactly
the same as 2257 joules per gram. So ...
When 1 gm of STEAM at 100 C condenses to
1 gm of liquid water at 100 C, it releases
2257 joules of heat energy to its environment.
Answer:
lymph nodes
tonsils and adenoids
thymus
Explanation:
-Arteries are the blood vessels that take the blood that contains oxygen from the heart to the tissues and are part of the circulatory system.
-Lymph nodes are glands that take care of filtering the fluid that goes through the lympathic system and are also important for the functioning of the immune system.
-Capillaries are blood vessels that connect the veins and arteries and are part of the circulatory system.
-Tonsils and adenoids are located in the throat and they help protect the body from diseases and they are part of immune system and the lympathic system.
-Veins are the vessels that take the blood to the heart and they are part of the circulatory system.
-Thymus is an organ in which the T cells develop and they help protect the body against virus and bacteria and it is part of the immune and lympathic systems.
According to this, cells or organs that are considered to be part of both the immune and lymphatic systems are:
lymph nodes
tonsils and adenoids
thymus
Think of a car, when we have to add oil. If we didn't then the friction would cause so much heat that the engine would break and fall apart.
