New ocean crust or sea floor is produced when tectonic plates ______

We drive at a speed of 20 km/h for 3 hours. Then we drive 4 hours at 30 km/h. Calculate our average speed.

Afina-wow [57]

First speed = 20km/h

Time = 3 hours

Distance = 3×20

Second speed = 30km/h

Time = 4 hours

Distance = 4×30

Total distance = 60+120 = <u>180km</u>

Total time = 3+4 =<u> 7 hours</u>

Average speed = 180/7

Hope this will help...

4 0

3 years ago

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A tree loses water to the air by the process of transpiration at the rate of 110 g/h. This water is replaced by the upward flow

Ksivusya [100]

Answer:

The answer is 1.87nm/s.

Explanation:

The $110g/hr$ water loss must be replaced by $110g/hr$ of sap. 110g of sap corresponds to a volume of

$110g \div \dfrac{1040*10^3g}{1*10^6cm^3} = 106cm^3$

thus rate of sap replacement is

$106cm^3/hr = 106*10^{-6}m^3/3600s = 2.94*10^{-8}m^3/s$

The volume of sap in the vessel of length $x$ is

$V = Ax$ ,

where $A$ is the cross sectional area of the vessel.

For 2000 such vessels, the volume is

$V = 2000Ax$

taking the derivative of both sides we get:

$\dfrac{dV}{dt} = 2000A \dfrac{dx}{dt}$

on the left-hand-side $\dfrac{dx}{dt}$ is the velocity $v$ of the sap, and on right-hand-side $\dfrac{dV}{dt} = 2.94*10^{-8}m^3/s$ ; therefore,

$2.94*10^{-8}m^3/s=2000Av$

and since the cross-sectional area is

$A = \pi (\dfrac{100*10^{-3}m}{2} )^2 = 7.85*10^{-3}m^2$ ;

therefore,

$2.94*10^{-8}m^3/s =2000(7.85*10^{-3}m^2)v$

solving for $v$ we get:

$v = \dfrac{2.94*10^{-8}m^3/s}{2000(7.85*10^{-3}m^2)}$

$\boxed{v =1.875*10^{-9}m/s = 1.875nm/s}$

which is the upward speed of the sap in each vessel.

8 0

3 years ago

so i had to work for halloween, my first Halloween working. When i got home my lil bro showed me all the candy he collected so i

Mrrafil [7]

Answer:

now that's a sweet little bro

4 0

2 years ago

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A car is strapped to a rocket (combined mass = 661 kg), and its kinetic energy is 66,120 J.

labwork [276]

Answer:

9.4 m/s

Explanation:

According to the work-energy theorem, the work done by external forces on a system is equal to the change in kinetic energy of the system.

Therefore we can write:

$W=K_f -K_i$

where in this case:

W = -36,733 J is the work done by the parachute (negative because it is opposite to the motion)

$K_i = 66,120 J$ is the initial kinetic energy of the car

$K_f$ is the final kinetic energy

Solving,

$K_f = K_i + W=66,120+(-36,733)=29387 J$

The final kinetic energy of the car can be written as

$K_f = \frac{1}{2}mv^2$

where

m = 661 kg is its mass

v is its final speed

Solving for v,

$v=\sqrt{\frac{2K_f}{m}}=\sqrt{\frac{2(29,387)}{661}}=9.4 m/s$

4 0

3 years ago

Why does the solar system consist of small planets orbiting close to sun and larger on more distant

ahrayia [7]

Answer:

The inner planets are smaller and rockier

Explanation:

Astronomers divide the planets into two groups in Solar system, the inner planets and outer planets. The inner planets are smaller and rockier and it is closer to the sun. The outer planets are larger , further far away and made of gas

The inner planets are Mercury, Venus , Earth and Mars. The outer planets Jupiter , Saturn , Uranus and Neptune comes after an asteroid belt. In some other planetary systems the gas are close to the sun.

particles in a disk of gas and dust will form Planets. If they orbit the star they are colliding and sticking. The stars wind blows away their gases . So the nearest planets to starts are rockier.

6 0

3 years ago

New ocean crust or sea floor is produced when tectonic plates _______. diverge converge