Because sound waves don't travel through the vaccume of space. Hope this helped
Answer:
It will take Andy 1.198minutes to mow the lawn and it will take Brian 1,209.98minutes to mow the same lawn.
Step-by-step explanation:
Using the simultaneous equation concept, let A denote Andy and B be Brian
Andy and Brian can mow the lawn for 1212minutes i.e A+B = 1212..eqn 1
If Brian would mow the lawn by himself in 1010 minutes more than it would take Andy, this means B=1010A...eqn 2.
Substituting eqn 2 into eqn 1
Equation 1 becomes
A+1010A=1212
1011A=1212
A=1212/1011
A=1.198
B = 1010×1.198
B=1,209.98
Therefore, It will take Andy 1.198minutes to mow the lawn and it will take Brian 1,209.98minutes to mow the same lawn.
Verrrrry interesting !
If the moon were replaced by something with a vastly greater mass
but at the same distance, then ...
-- The period of its revolution around the Earth would be much shorter.
That is, it would orbit the Earth in much less than 27.3 days. We might
see it go through a complete set of phases in 2 weeks, or even 1 week.
-- The ocean tides would be much greater. Low tides would be
much lower, and high tides would be much higher.
-- Sadly, the land tides, and the forces on the Earth's internal structure,
would also be much greater. That means great increases in earthquake
and volcanic activity.
-- The Earth and moon both revolve around their common center of
mass. Under the current arrangement ... with the Earth having 80 times
the mass of the Moon ... that point is inside the Earth, and it looks a lot
like the Moon is orbiting a stationary Earth.
When the new body arrives to replace the lightweight Moon, that point
will be a lot closer to the new companion ... maybe even inside it.
Then, it will look a lot like the monster is the stationary one, and the
Earth is orbiting it.
I actually don't believe that we would SEE that change, or feel it.
Change in velocity = Final velocity - Initial velocity
Initial velocity = 20 m/s
Final velocity = 10 m/s
Change in velocity = 10 - 20 = -10m/s
Correct option B
Hope This Helps You!
Answer:
6.25 m/s
Explanation:
mass of man (m1) = 80 kg
mass of boy (m2) = 20 kg
mass of man and boy after collision (m12)= 20 + 80 = 100 kg
velocity of man and boy after collision (v) = 2.5 m/s
angle θ = 60 °
How fast was the boy moving just before the collision
?
- From the diagram attached, the first image shows the man and the boys motion while the second diagram shows their motion rearranged to form a triangle. With the momentum of the man and the boy forming the sides of the triangle.
- M₁₂ = total momentum after collision = m12 x v = 100 x 2.5 = 250
- Mboy = momentum of the boy before collision = m2 x Velocity of boy
- Mman = momentum of the man before collision = m1 x velocity of man
- from the triangle, cos θ =
cos 60 = 
Mboy = 250 x cos 60 = 125
- recall that momentum of the boy (Mboy) also = m2 x Velocity of boy
therefore
125 = 20 x velocity of boy
velocity of boy = 125 / 20 = 6.25 m/s
