All categories

2 years ago

How does water get to the tops of the tallest trees against the force of gravity

2 answers:

4 0

Water gets to the leaves in the tops of the tallest trees by something called the cohesion-tension theory. Water has two very unique properties called adhesion and cohesion. Cohesion is the tendency of water molecules to stick together with one another. The water sticks together, leaving no room for air, strengthening the "force" of the water going up the tree. The water also sticks to the sides of the xylem inside the tree. In addition to these properties, there are also the factors of negative and positive water potential. For more information, look up more details of the cohesion-tension theory.

tatyana61 [14]2 years ago

4 0

You might be interested in

I would like help with this physics problem

Darina [25.2K]

(a) This is a freefall problem in disguise - when the ball returns to its original position, it will be going at the same speed but in the opposite direction. So the ball's final velocity is the negative of its initial velocity.

Recall that

$v_f=v_i+at$

We have $v_f=-v_i$ , so that

$-2v_i=at\implies-2\left(8\,\dfrac{\mathrm m}{\mathrm s}\right)=\left(-2\,\dfrac{\mathrm m}{\mathrm s^2}\right)t\implies t=8\,\mathrm s$

(b) The speed of the ball at the start and at the end of the roll are the same 8 m/s, so the average speed is also 8 m/s.

(d) The position of the ball $x_f$ at time $t$ is given by

$x_f=x_i+v_it+\dfrac12at^2$

Take the starting position to be the origin, $x_i=0$ . Then after 6 seconds,

$x_f=\left(8\,\dfrac{\mathrm m}{\mathrm s}\right)(6\,\mathrm s)+\dfrac12\left(-2\,\dfrac{\mathrm m}{\mathrm s^2}\right)(6\,\mathrm s)^2=42\,\mathrm m$

so the ball is 42 m away from where it started.

We're not asked to say in which direction it's moving at this point, but just out of curiosity we can determine that too:

$x_f-x_i=\dfrac{v_i+v_f}2t\implies42\,\mathrm m=\dfrac{8\,\frac{\mathrm m}{\mathrm s}+v_f}2(6\,\mathrm s)\implies v_f=6\,\dfrac{\mathrm m}{\mathrm s}$

Since the velocity is positive, the ball is still moving up the incline.

8 0

3 years ago

Một bóng đèn có hiệu điện thế định mức là 110V. Đặt vào hai đầu bóng đèn các hiệu điện thế sau đây, hỏi trường hợp nào dây tóc c

Leokris [45]

Answer:

fhaiisjrbekxkrkebxnsiiwj4bnds

8 0

2 years ago

An astronaut is stationary in space. Which of these would have the greatest speed as observed by the astronaut?

yaroslaw [1]

Hello!

The answer that makes most sense to me is option A.

~ Hope I helped! ~

7 0

3 years ago

Read 2 more answers

When a wave strikes a new medium, three things can happen: reflection, transmission, and absorption. Consider an echo. Do you th

kolbaska11 [484]

Answer:

YES

Explanation:

An echo may be defined as a sound which is repeated because of the sound waves that are produced are reflected back after striking a surface. Sound waves can smoothly bounce off the hard objects in the same manner as a rubber ball bounces back the ground.

When a sound wave strikes a hard surface, the sound waves gets reflected back and bounces back to the observer and produces an echo. If the sound waves strikes a soft surface it absorbs the sound.

Although the direction of a sound changes but the echo sounds in the same way as the original sound.

7 0

3 years ago

Two children stretch a jump rope between them and send wave pulses back and forth on it. The rope is 4.5 m long, its mass is 0.4

lions [1.4K]

Answer:

density = 0.0933 kg/m

speed = 27.581 m/s

Explanation:

given data

length L = 4.5 m

mass m = 0.42 kg

force F = 71 N

to find out

mass density and speed

solution

we find linear mass density

linear mass density = mass / length

put here all value

density = 0.42 / 4.5

density = 0.0933 kg/m

and

speed of wave

speed = √(F/density)

speed = √(0.42/0.933)

speed = 27.581 m/s

7 0

2 years ago