Which metal and nonmetal families are the most different and why

. The Soviet Yuri Gagarin was the first human to orbit Earth true or false

Dmitrij [34]

Answer:

true , I searched and got u the answer

3 0

2 years ago

In a mixture of the gases oxygen and helium, which statement is valid: (a) the helium molecules will be moving faster than the o

mixer [17]

Answer:

a

Explanation:

Given:

In a mixture of the gases oxygen and helium, which statement is valid:

(a) the helium molecules will be moving faster than the oxygen molecules, on average

(b) both kinds of molecules will be moving at the same speed

(c) the oxygen molecules will, on average, be moving more rapidly than the helium molecules

(d) the kinetic energy of the helium will exceed that of the oxygen

(e) none of the above

Solution:

- We will use Boltzmann distribution to answer this question. The root mean square speed of molecules of a gas gives the average speed as follows:

V_rms = sqrt ( 3 k T / m )

- Where, k is the Boltzmann constant, T is the temperature and m is the mass of a single molecule of a gas.

- In general, a mixture has a constant equilibrium temperature T_eq.

- So the v_rms is governed by the mass of a single molecule.

- We know that mass of single molecule of Oxygen is higher than that of Helium molecule. Hence, the relation of mass is inversely proportional to square of root mean speed. So the helium molecules will be moving faster than the oxygen molecules.

- Note: The kinetic energy of the mixture remains constant because it is due to the interaction of the molecules within i.e oxygen and helium. Which makes the kinetic energy independent of mass.

E_k = 0.5*m*v_rms^2

E_k = 0.5*m*(3*k*T/ m )

E_k = 0.5*3*k*T

Hence, E_k is only the function of Temperature which we already established to remain constant at equilibrium.

8 0

3 years ago

A firecracker in a coconut blows the coconut into three pieces. Twopieces of equal mass fly off south and west, perpendicular to

loris [4]

Answer:

V = 13m/s

North-East (i.e. 45 degree from North)

Explanation:

This question deals with the idea of momentum.

Since the directions of a compass are fixed, we can take south as horizontal and west as vertical. Since both pieces of coconut are of equal mass, then the resultant of the two pieces would be in between South and West and the third piece would be opposite this direction and be in the North-East (i.e. 45 degree from North) direction

To find the speed of the third piece, we first find the speed on the two pieces of the coconut in terms of $V_{x}$ (horizontal component of velocity) and $V_{y}$ (vertical component of velocity)

We have

$V_{y}$ = Velocity in South direction = 18m/s

$m_{y}$ = Mass of piece in South direction = m

$V_{x}$ = Velocity in West direction = 18m/s

$m_{x}$ = Mass of piece in West direction = m

$V_{ry}$ = Velocity of Third Piece in North direction = unknown

$V_{rx}$ = Velocity of Third Piece in East direction = unknown

$m$ = Mass of third piece = 2m

$mV_{ry} = m_{y} V_{y} \\ 2mV_{ry} = m18\\ V_{ry} = 9$

$mV_{rx} = m_{x} V_{x} \\ 2mV_{rx} = m18\\ V_{rx} = 9$

Since we now know the horizontal and vertical component of the velocity of the third piece of coconut we find the resultant velocity. Since we know the direction is North-East, we can imagine a right angled triangle with base of 9 and height 9 and the hypotenuse equal to the resultant velocity .

We can simply apply the Pythagoras theorem and find the hypotenuse

$Hypotenuse^{2} = Height^{2} + Base^{2} \\ V_{3}^2 = 9^{2} + 9^{2} \\ V = 12.728 m/s$

V = 13m/s

6 0

3 years ago

Susan

maxonik [38]

D. Was a leader in the woman's suffrage movement

7 0

3 years ago

Bullets from two revolvers are fired with the same velocity. The bullet from gun #1 is twice as heavy as the bullet from gun #2.

IrinaVladis [17]

Answer:

option C

Explanation:

Let mass of the bullet be m and velocity be v

mass of gun be M and bullet be V

now,

using conservation of momentum for gun 1

(M+m) V' = 2 mv + 3 MV

V' = 0

3 M V = - 2 mv

momentum of gun 1 =- 2 mv---------(1)

now for gun 2

(M+m) V' = mv + MV

V' = 0

M V = - mv

momentum of gun 1 = -mv-----------(2)

dividing equation (1) by (2)

$\dfrac{P_m1}{P_m2} = \dfrac{- 2mv}{-mv}$

$\dfrac{P_m1}{P_m2} = \dfrac{2}{1}$

the correct answer is option C

7 0

3 years ago