Answer:
14.36m/s
Explanation:
From the law of conservation of linear momentum
m1u1 + m2u2 = v(m1 + m2)
68×17 + 76×12= v(68+76)
1156+912 = 144v
2068 = 144v
v = 2068/144
=14.36 m/s
Which element is less reactive, an element whose atoms have seven valence electrons or an element whose atoms have eight valence electrons? Why?<span>an element with 8 valence electrons because it doesn't require any additional electrons to become stable</span>
As we know that in transformers we have

here we know that




now from above equation we will have


now we have to reduce this voltage to final voltage of V = 4 V
so again we will have



so we need to take such a winding whose ratio is 1:5
So it is satisfied in X


so answer will be
<u>B)- X</u>
Answer:
Hubble measured the velocity of the movement of galaxies by using Hubble's law states that galaxies located farthest from the center of the universe than those closest to the center.
Explanation:
Hubble's Law says that an object's velocity away from an observer is directly proportional to its distance from the observer. In other words, the farther away something is the faster it is moving away from us. The spectrum of a galaxy allows you to measure its redshift.
Answer:
.
Explanation:
When the ball is placed in this pool of water, part of the ball would be beneath the surface of the pool. The volume of the water that this ball displaced is equal to the volume of the ball that is beneath the water surface.
The buoyancy force on this ball would be equal in magnitude to the weight of water that this ball has displaced.
Let
denote the mass of this ball. Let
denote the mass of water that this ball has displaced.
Let
denote the gravitational field strength. The weight of this ball would be
. Likewise, the weight of water displaced would be
.
For this ball to stay afloat, the buoyancy force on this ball should be greater than or equal to the weight of this ball. In other words:
.
At the same time, buoyancy is equal in magnitude the the weight of water displaced. Thus:
.
Therefore:
.
.
In other words, the mass of water that this ball displaced should be greater than or equal to the mass of of the ball. Let
denote the density of water. The volume of water that this ball should displace would be:
.
Given that
while
:
.
In other words, for this ball to stay afloat, at least
of the volume of this ball should be under water. Therefore, the volume of this ball should be at least
.