Refer to the figure shown below.
Let V = speed of the boat relative to the water
Given:
u = 1 km/h the speed of flowing water.
When traveling downstream from A to B, the actual speed of the boat is
V₁ = V + u = V + 1 km/h
When traveling upstream from B to A, the actual speed of the boat is
V₂ = V - u =V - 1 km/h
Because the distance Ab is 1 km, the time taken for the round trip is
t = (1 km)/(V+1 km/h) + (1 km)/(v-1 km/h)
= (V-1 + V+1)/(V² - 1)
= (2V)/(V² - 1)
The time for the round trip is 50 min = 5/6 h.
Therefore
(2V)/(V² - 1) = 5/6
5(V² - 1) = 12V
5V² - 12V - 5 = 0
Solve with the quadratic formula.
V = (1/10)*[12 +/- √(144 + 100)] = 2.762 or -0.362 km/h
Ignore negative speed, so that
V = 2.762 k/h
Answer:
The speed of the boat relative to the water is
2.76 km/h (nearest hundredth)
Answer:
A. Both exceed the matter-energy equivalent of luminous matter.
B. Dark matter has only an attractive gravitational effect, while dark energy is repulsive.
Explanation:
Dark matter and dark energy together constitute about ninety-five percent of the of total matter-energy equivalence in the universe. So, they exceed the matter-energy equivalent of luminous matter.
Dark energy is the repulsive force that is accelerating the expansion of the universe. Dark matter only has an attractive gravitational effect but does not interact with light of any kind.
Answer:
B. ceramics
Explanation:
Ceramics are materials which are inorganic and non-metallic materials made from compounds of metals and non metals. They are usually oxides, carbides and nitrides. They are stronger, harder and more resistant to heat than a wide variety of other types of materials. They found a great use in the industry such as for making glass wares, pottery , valves, spark plugs, pressure sensors, vibration sensors,bricks, cement,insulators, resistors, superconductors, capacitors ,ceramic rotors e.t.c.
Answer:
variable
Explanation:
Globular clusters is defined as collection of numerous star that revolve around the galaxy core. they are so bound to each other that they formed spherical shape. This boundness among the star is due to gravity. The main characteristics of globular cluster is that they contain high density of star at center.
Every galaxy consist of various number of globular cluster and even milky way consist of 125 to 200 cluster