a una velocidad de
22 m/s, quien lo golpea y devuelve en la misma
dirección con una velocidad de 14 m/s. Si el
tiempo de contacto del balón con la jugadora es
de 0,03 s, ¿con qué fuerza golpeó la jugadora el
balón?
21 Una bala de 0,8 g, está en la recámara de un rifl e
cuando se g
Answer:
Explanation:
If the dragster attains the speed equal to that of the car which is moving with constant velocity of v₀ , before the two close in contact with each othe , there will not be collision .
So the dragster starting from rest , must attain the velocity v₀ in the maximum time given that is tmax .
v = u + a t
v₀ = 0 + a tmax
tmax = v₀ / a
The value of tmax is v₀ / a .
Answer:
r2 = 1 m
therefore the electron that comes with velocity does not reach the origin, it stops when it reaches the position of the electron at x = 1m
Explanation:
For this exercise we must use conservation of energy
the electric potential energy is
U = 
for the proton at x = -1 m
U₁ =
for the electron at x = 1 m
U₂ = 
starting point.
Em₀ = K + U₁ + U₂
Em₀ = 
final point
Em_f = 
energy is conserved
Em₀ = Em_f
\frac{1}{2} m v^2 - k \frac{e^2}{r+1} + k \frac{e^2}{r-1} = k e^2 (- \frac{1}{r_2 +1} + \frac{1}{r_2 -1})
\frac{1}{2} m v^2 - k \frac{e^2}{r+1} + k \frac{e^2}{r-1} = k e²( 
)
we substitute the values
½ 9.1 10⁻³¹ 450 + 9 10⁹ (1.6 10⁻¹⁹)² [ 
) = 9 109 (1.6 10-19) ²( 
)
2.0475 10⁻²⁸ + 2.304 10⁻³⁷ (5.0125 10⁻³) = 4.608 10⁻³⁷ ( 
)
2.0475 10⁻²⁸ + 1.1549 10⁻³⁹ = 4.608 10⁻³⁷
r₂² -1 = (4.443 10⁸)⁻¹
r2 = 
r2 = 1 m
therefore the electron that comes with velocity does not reach the origin, it stops when it reaches the position of the electron at x = 1m
The answers are as follows:
1. B.
A typical atom is made up of three different particles, which are electron, proton and neutron. The proton and the neutron are located inside the nucleus of the atom while the electron orbit round the nucleus.
2. C
The number of proton in an atom determines the atomic number of that atom. Atom are positively charged particles and they do no participate in chemical reactions. The number of proton of an element remain constant at all time while the number of neutrons and the electrons in the atom may change.
3. B.
The first periodic table was created by Dmitri. He arranged the periodic table in such a way that, elements with similar properties fall into the same column in his periodic table. This was because, he arranged the periodic table on the basis of their physical and chemical properties.
4. A
The elements in the periodic table are arranged in horizontal row and vertical column. The column on the periodic table divides the elements into groups.
A row of element on the periodic table is called PERIOD. For elements on the same period, they have the same number of atomic orbitals.
5. A
Chemical symbol refers to the one or two letters which are used to represent a particular element. Chemical symbols are derived in a variety of ways. The chemical symbols make it possible for one to recognize an element quickly and to write it in an abbreviated form when writing chemical equations.
6. A.
An object is said to be ductile if it can be pulled into a long wire. It refers to an element's capacity to be pulled into a thin wire without the element been deformed. This is one of the properties of metals. Ductability makes it easier for one to work with a metal.
7. C
When metals atoms react with other atoms, the metal atoms lose electrons, this is because, metals usually have a low number of electrons in their outermost shells, which they always preferred to donate in order to achieve octet form.
8. B
Particle accelerator is a machine that accelerate elementary particles to very high energies, thus producing beam of charged particles which can be used for a lot of different purposes.
Answer:
1600 kg
Explanation:
use the formula p=mv. p=3200, v=2. Plug in and rearrange.
3200=(m)(2)
m= 3200/2
m=1600
