Answer:
Concrete
Explanation:
The speed at which sound propagates is medium dependent. As one of the forms of mechanical waves, sound requires a material medium for propagation from place to place.
- Sound travels with the least speed in air because air particles are far apart and they are randomized.
- Sound travels with the greatest speed in solids. Concrete is the only solid material given in the choice.
The speed of sound increases from air to liquid and to solid.
Answer:
25 N; 250 W.
Explanation: Work Done
=
Force
×
Displacement
×
cos
(
The angle between Force and Displacement
)
So, Let's Assume the Force to be
x
Newtons.
So, According to The Sum,
×
x
x
⋅
100
=
2500
⇒
x
=
25
00
1
00
=
25
So, The force was
25
N
.
And, We also know,
Power
=
Work Done
Time
So,
The Power of the Machine =
2500
10
Watts
=
250
Watts
Answer:
Since strong nuclear forces involve only nuclear particles (not electrons, bonds, etc) items 3 and 4 are eliminated.
Again item 2 refers to bonds between atoms and is eliminated.
This leaves only item 1.
Nuclear forces are very short range forces between components of the nucleus.
Weak nuclear forces are trillions of times smaller than strong forces.
Gravitational forces are much much smaller than the weak nuclear force.
The activation energy is 10 kJ and the reaction is exothermic.
<span>Let's put it this way. Say you have a killer-whale and a penguin. Killer-whales are major predators to penguins. Now, say the killer-whale population increases. The penguins would be eaten more by the killer-whales, then causing a population decrease for the penguins. If the population decreases, they're won't be enough penguins, and they most likely will become extinct, as well as causing a population decrease for the killer-whales as well. Whereas, vis versa, they're were a killer-whale population decrease. The penguins would be less hunted, therefore, creating a population increase for the penguins.</span>
