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3 years ago

What is the difference between a group and a period

1 answer:

5 0

Periods going left to right. The periodic table also has a special name for its vertical columns. Each column is called a group. The elements in eachgroup have the same number of electrons in the outer orbital.

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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

A seesaw is 4.0m long with a pivot at its midpoint. A boy who weighs 400N sits at a distance of 1.5m from the pivot. His sister

bezimeni [28]

Answer:

the girl must sit 2 cm from the pivot at the opposite end of the seesaw.

Explanation:

Given;

length of the seesaw, L = 4.0 m

weight of the boy, W₁ = 400 N

position of the boy from the pivot, d₁ = 1.5 m

weight of her sister, W₂ = 300 N

First, make a sketch of this information given;

0---0.5m---------------------Δ--------------------------4m

↓<--------1.5m-------> <---------x--------->↓

400 N 300N

Apply the principle of moment about the pivot, to determine the value of x;

Sum of anticlockwise moment = sum of clockwise moment

400(1.5) = 300(x)

600 = 300x

x = 600/300

x = 2 cm

Thus, the girl must sit 2 cm from the pivot at the opposite end of the seesaw.

8 0

3 years ago

The molecular weight of carbon dioxide (CO2) is 44.00 a.m.u., and the molecular weight of propane gas (C3H8) is 44.10 a.m.u. Thu

Nina [5.8K]

The molecular weight of carbon dioxide (CO2) is 44.00 a.m.u., and the molecular weight of propane gas (C3H8) is 44.10 a.m.u. Thus CO2 diffuses_______ C3H8.

Slower Than

Faster Than

The Same As

Slower than

6 0

3 years ago

Read 2 more answers

A toy car is moving along with 0. 50 joules of kinetic energy. If its speed is doubled, then its new kinetic energy is.

antoniya [11.8K]

Answer:

2 Joules

Explanation:

Kinetic Energy = 1/2 of (Mass x Velocity^2)

7 0

2 years ago

A bicycle rider travels 50.0 km in 2.5 hours. What is the cyclists speed

krek1111 [17]

Hi,
Recall the formula V=d/t, where V stands for velocity or speed, d stands for distance and t stands for time. By substituting your values you get: V=50.0km/2.5h, which equals to 20km/h.

7 0

3 years ago