The map above, shows the location of Brazil's major resources and industries. Where is most of Brazil's sugarcane grown?

Driving home from school one day, you spot a ball rolling out into the street (Figure 5-21). You brake for 1.20 s, slowing your

frosja888 [35]

A ) v = v o + a t ( the acceleration will be negative )
9.50 = 16.0 + a * 1.2
a * 1.2 = -16.0 + 9.50
a * 1.2 = - 6.5
a = - 6.5 : 1.2
a = - 5.4167 m/s²
F = m * a = 950 kg * 5.4167 m/s²
F = 5,145.8 N ( the average force exerted on a car during braking )
b ) d = v o - a t² / 2
d = 16.0 * 1.2 - ( 5.4167 * 1.2² / 2 ) =
= 19.20 - 3.90 = 15.30 m

7 0

3 years ago

A ray of light traveling in air strikes the surface of a liquid. if the angle of incidence is 29.7◦ and the angle of refraction

lana66690 [7]

When light moves from a medium with higher refractive index to a medium with lower refractive index, the critical angle is the angle above which there is no refracted ray, and it is given by:
$\theta_c = \arcsin ( \frac{n_r}{n_i} )$ (2)
where $n_r$ is the refractive index of the second medium and $n_i$ is the refractive index of the first medium.

We can find the ratio $n_r / n_i$ by using Snell's law:
$n_i \sin \theta_i = n_r \sin \theta_r$ (1)
where
$\theta_i$ is the angle of incidence
$\theta_r$ is the angle of refraction

By using the data of the problem and re-arranging (1), we find
$\frac{n_r}{n_i} = \frac{\sin \theta_i}{\sin \theta_r} = \frac{\sin 16.3^{\circ}}{\sin 29.7^{\circ}} =0.566$

and if we use eq.(2) we can now find the value of the critical angle:
$\theta_c = \arcsin ( \frac{n_r}{n_i} ) = \arcsin (0.566) = 34.5^{\circ}$

3 0

3 years ago

Newton’s empirical law of cooling/warming of an object is given by ( ), T Tm k dt dT = − where k is a constant of proportionalit

pychu [463]

Answer:

The time for the cake to cool off to room temperature is

approximately 30 minutes.

Let $T_{0}$ = $70^{0}$ F be the temperature and T that of the body

Explanation:

Our Tm = 70, the initial-value problem is

$\frac{DT}{dt}$ = k(T − 70), T(0) = 300

Solving the equation, we get

$\frac{DT}{t-70}$ = kdt

In [T-70]= kt + $C_{1}$

T = 70 + $C_{2}$ $e^{kt}$

Finding he value for $C_{2}$ using the initial value of T (0)= 300, therefore we get:

300=70+ $C_{2}$

$C_{2}$ = 230 therefore

T= 70+ 230 $e^{kt}$

Finding the value for k using T (3) = 200, therefore we get

T (3) = 200

$e^{3k}$ = $\frac{13}{23}$

K = $\frac{1}{3}$ in $\frac{13}{23}$

= -0.19018

Therefore

T(t) = 70+230 $e^{-0.19018}$

4 0

2 years ago

Gravitational potential energy is a form of potential energy

Gre4nikov [31]

True because it has "falling" ability

5 0

3 years ago

Why does water feel cool when it evaporates

Illusion [34]

First, it makes your skin feel cooler when it's wet. And when it evaporates it removes some heat. But sweat will only evaporate in an environment where there isn't muchwater in the air. In a place with high humidity, there're already lots of water molecules in the air.

4 0

2 years ago

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