Answer:
Explanation:
The speed is the same coming back down to the ground as it would be when thrown up.
A little later, you will be studying energy. One of the things conserved in a system is energy. You cannot get more energy out of a system than you have put in.
That fact explains how the speed at the end of the object's travels can be the same as the beginning. All energy must be accounted for.
The second part is not so easily proved or even shown easily. It can be indicated, though.
Suppose vi = 40 m/s
Suppose vf = 0 m/s In other words, you throw a rock up and you stop timing it when it reaches its maximum height.
a = - 9.81 Gravity goes in the opposite direction to vi
vf = vi^2 + 2*a*d
0 = 1600 - 2*9.81*d
-1600 = -19.62*d
1600 / 19.62 = d
d = 81.55 m.
Now leave everything else alone and double vi
0 = 80^2 - 2*9.81 d
-6400 = -19.62 * d
d = 326.2
Give or take a bit, the height = roughly 4 times what it was if the initial speed is doubled. 326.2 / 81.55 = 4
That the Earth was the center of the universe.
Answer: Earth
No problem, and you already know all about it.
Here are a few examples of same volume / different weight:
-- A bottle full of water is heavier than the same bottle when it's full of air.
-- Stones are heavier than styrofoam chunks the same size.
-- A bowl of meat loaf is heavier than a bowl of scrambled eggs.
In each example, two things have the same volume, but one weighs more than
the other. I didn't say anything about mass yet, but that's easy: As long as you
keep everything on Earth, more weight means more mass.
So how come, in each example, things with the same volume have different mass ?
This was your original question.
The answer is just the simple fact that there are millions of different substances, and
each different substance packs a different amount of mass into the same volume.
The amount of mass that a substance packs into a standard volume is called
the <em>density</em> of the substance. Meat loaf is more dense than scrambled eggs.
Stone is more dense than styrofoam. Water is more dense than air. And <em>gold</em>
is 19 times as dense as water. If you have a jar that holds a pound of water, and
you pour out the water and fill the jar with gold, the same jar holds 19 pounds of gold,
because the density of gold is 19 times the density of water.
The reason you were assigned to think about this question for homework is that
next time your Physics class meets, you'll start talking about <em>Density. </em><em /> And you're
all ready for it now.
Answer: because of gravity
Answer:
The force on q₁ due to q₂ is (0.00973i + 0.02798j) N
Explanation:
F₂₁ =
Where;
F₂₁ is the vector force on q₁ due to q₂
K is the coulomb's constant = 8.99 X 10⁹ Nm²/C²
r₂₁ is the unit vector
|r₂₁| is the magnitude of the unit vector
|q₁| is the absolute charge on point charge one
|q₂| is the absolute charge on point charge two
r₂₁ = [(9-5)i +(7.4-(-4))j] = (4i + 11.5j)
|r₂₁| =
(|r₂₁|)² = 148.25
= 0.050938(0.19107i + 0.54933j) N
= (0.00973i + 0.02798j) N
Therefore, the force on q₁ due to q₂ is (0.00973i + 0.02798j) N