Answer:
False
Explanation:
According to the big bang theory, matter was an infinitely small and very high density point which at one point exploded and expanded in all directions, creating what we know as our Universe, which also includes space and time . This happened about 13.8 billion years ago. Theoretical physicists have managed to reconstruct this chronology of events from 1/100 of a second after the Big Bang. After the explosion, while the Universe expanded, it cooled sufficiently and the first subatomic particles were formed: Electrons, Positrons, Mesons, Barions, Neutrinos, Photons among others. Today more than 90 particles are known. This theory solves many unknowns and is very well received by the scientific community, however there is still much to solve, for example, one of the great unsolved scientific problems in the expanding Universe model is whether the Universe is open or closed.
An attempt to solve this problem is to determine if the average density of matter in the Universe is greater than the critical value in Friedmann's model. The mass of a galaxy can be measured by observing the movement of its stars; multiplying the mass of each galaxy by the number of galaxies, it is seen that the density is only 5 to 10% of the critical value.
As you increase the temperature, the matter begins to expand. Due to this, the distance between matter particles decreases and they are no more compact. Hence, density decreases.
The first one is actually 10 times as big as the second one.
Because of their places, the first one means 6000, and the second one means 600.
Answer:
1) The strength of the electromagnet increases → Place a magnetic core inside the coil of wire
2) The electromagnet turns off → Turn off the battery supply
3) The poles of the electromagnet reverse → Change the direction in which the current flows
Explanation:
when current passes through a coil it behaves a an electromagnet.
Magnetic field strength is given by
B = μ N I
N is no of turns and
I is the current through coil
μ is permeability of the medium or core in the coil.
1). Magnetic core increase permeability μ so it will strengthen magnetic field:
B = <u>μ</u> N I
2). When the battery turns off current becomes zeroi.e I=0
So B = μ N * 0
⇒ B = 0
so electromagnet turns off
3). Direction of magnetic field can be determine by right hand rule, i.e curl the fingers in the direction of current, thumb will point in the direction of north pole.
so changing current direction will change direction of magnetic field.
Answer:
The resulting velocity of the ball after it hits the racket was of V= 51.6 m/s
Explanation:
m= 55.6 g = 0.0556 kg
t= 2.8 ms = 2.8 * 10⁻³ s
F= 1290 N/ms * t - 330 N/ms² * t²
F= 1024.8 N
F*t= m * V
V= F*t/m
V= 51.6 m/s
