If you run the 100 m track at a velocity of 5.0 m/s, what is the time needed?

A hippo drives 42 km due East. He then turns and drives 28 km at 25° East of South. He turns again and drives 32 km at 40° North

ch4aika [34]

Answer:

a) Please, see the attched figure

b) Total displacement R = (78.3 km; -4.8 km)

c) R = (78.4 km * cos (-3.5°); 78.4 km * sin (-3.5°))

d) The hippo is 78.4 km from his starting point.

The total distance traveled is 102 km

Explanation:

a)Please, see the attached figure.

b) The vector A can be expressed as:

A = (magnitude * cos α; magnitude * sin α)

Where

magnitude = 42 km

α= 0

Then,

A = (42 km ; 0) or 42 km i

In the same way, we can proceed with the other vectors:

B = ( Bx ; By)

where

(apply trigonometry of right triangles: sen α = opposite / hypotenuse and

cos α = adjacent / hypotenuse. See the figure to determine which component of vector B is the opposite and adjacent side to α)

Bx = 28 km * sin 25 = 11.8 km

By = 28 km * cos 25 = -25.4 km (it has to be negative since it is directed towards the negative vertical region according to our reference system)

B = (11.8 km; -25.4 km) or 11.8 km i - 25.4 km j

C = (Cx; Cy)

where

Cx = 32 km * cos 40° = 24.5 km

Cy = 32 km * sin 40 = 20.6 km

C = (24.5 km; 20.6 km)

Then:

R = A+B+C = (42 km + 11.8 km + 24.5 km; 0 - 25.4 km + 20.6 km)

= (78.3 km; -4.8 km) or 78.3 km i -4.8 km j

c) R = (78.3 km; -4.8 km)

The magnitude of R is:

$magnitude = \sqrt{(78.3)^{2 }+ (-4.8)^{2}}= 78.4 km$

Using trigonometry, we can calculate the angle:

Knowing that

tan α = opposite / adjacent

and that

opposite = Ry = -4.8 km

adjacent = Rx = 78.3 km

Then:

tan α = -4.8 km / 78.4 km

α = -3.5°

We can now write the vector R in magnitude and direction form:

R = (78.4 km * cos (-3.5°); 78.4 km * sin (-3.5°))

d) The displacement of the hipo relative to the starting point is the magnitude of vector R calculated in c):

magnitude R = 78. 4 km

The total distance traveled is the sum of the magnitudes of each vector:

Total distance = 42 km + 28 km + 32 km = 102 km

3 0

3 years ago

A 1,700 kg car is being used to give a 1,400 kg car a push start by exerting a force of

Gwar [14]

Answer:

- 670 kg.m/s

Explanation:

Newton's third law states that to every action, there is equal and opposite reaction force. Since the force will be same but different in direction and acted in the same time then the impulses ( force multiply by time) of the two car be same in magnitude but different in direction - 670 kg.m/s

5 0

3 years ago

How would improvement in use of renewable energy sources impact climate change sea-level rise?

bonufazy [111]

Answer:

Almost immeasurably small.

Explanation:

The STORY is that humans are BAD for the environment and have caused a HUGE change in the amount of CO₂ in the atmosphere.

Let's look at the reports and draw our own conclusions.

Current CO₂ levels are 409.8 parts per million (PPM)

at the beginning of the Industrial revolution in the 1700's, the presumed beginning of the huge increase in CO₂ the level was about 280 PPM

For perspective lets assume we capture the whole atmosphere and squish it down to 2400 one liter bottles of air

That's 100 cases of 24 bottles per case.

We now separate all the air components into their own bottles

Nitrogen is 78% of our air, so we subtract 78 cases from our 100 leaving 22

Subtracting Oxygen at 21% of air leaves 1 case of liter bottles left

Of those 24 bottles, Argon makes up 0.93% of air so we subtract 22 bottles

The remaining two bottles contain all of the other gasses in our air, One of those bottles contains CO₂.

If we take the CO₂ levels from the 1700's at about 280 PPM as a baseline and assume ALL of the increase is human caused, that is (410 -280) / 280 = 46 % of the total.

The human caused addition of CO₂ would be 460 mililiters out of 2400 liters over the course of 250 years

The claim is, that less than half of a liter of CO₂ out of 2400 liters of air is responsible for heating not only the gas in all the other bottles but also the surface of the earth itself.

Personally, it boggles my mind.

And it says NOTHING of a far more powerful greenhouse gas that is far more prevalent in the atmosphere...water vapor.

Water vapor is about 1% of air at sea level and about 0.4% overall. It was not considered in the above analysis because water vapor can condense out and is not a constant in the air.

Notice that there is about 100 times the amount of water vapor in the air as compared to CO₂. Water vapor also has between 4 and 8 times the greenhouse effect that CO₂ does.

Makes one wonder why we choose to pick on CO₂.

7 0

3 years ago

If a 0.15 kg ball falls and has a KE of 20 J just before striking the ground, from what height did it fall. A. 1.36m B. 3m C. 13

RUDIKE [14]

According to the conservation of mechanical energy, the kinetic energy just before the ball strikes the ground is equal to the potential energy just before it fell.

Therefore, we can say KE = PE
We know that PE = m·g·h

Which means KE = m·g·h

We can solve for h:

h = KE / m·g
= 20 / (0.15 · 9.8)
= 13.6m

The correct answer is: the ball has fallen from a height of 13.6m.

5 0

3 years ago

rocks move trough the rock cycle through uplift,folding,and faulting cased by movements of the earth´s________

garik1379 [7]

Tectonic plates and convection cells move tectonic plates

4 0

3 years ago