What best describes gravity?

If a rock is thrown vertically upward from the surface of Mars with velocity 15 mys, its height after t seconds is h − 15t 2 1.8

mr Goodwill [35]

Answer: a) 7.56m/s b) 6.245m/s on its way up and -6.245m/s on its way down.

Explanation:

a) Velocity after 2 seconds

H = 15t - 1.86t^2

V(0) = 15 m/s

Now let’s first differentiate h with respect to t , we have

d/dt x h = d/dt (15t - 1.86t^2)

= 15 d/dt x t - 1.86 d/dt x t^2

= 15 x 1 - 1.86(2t) = 15 - 3.72t

t = 2 sec

Therefore

V(t) = 15 - 3.72(2) = 7.56 m/s

b) if height is 25m

H = 15t - 1.86t^2

Therefore h = 25, we have

25 = 15t - 1.86t^2

15t - 1.86t^2 - 25 = 0

1500t - 186t^2 - 2500 = 0

-186t^2 + 1500t - 2500 = 0

Using quadratic equation to find the roots of equation

First root t1 = 2.3535

Second root T2 = 5.71102

Now, at t1,

V(t1) = 15 - 3.72 (2.3535) = 6.245 m/s

The velocity of the rock on its way up is 6.245 m/s

V(T2) = 15 - 3.72 (5.71102) = -6.245 m/s

The velocity of the rock on its way down is -6.245 m/s

8 0

4 years ago

Which of the following is a component of staying positive while competing

Natalija [7]

Answer: B - complimenting others on good plays

Explanation: Reading the first words sort of give it away when staying positive you compliment, not criticize, confront angrily, or refuse.

4 0

3 years ago

Read 2 more answers

Sunshine Corporation is expected to pay a dividend of $1.50 in the upcoming year. Dividends are expected to grow at the rate of

grigory [225]

Answer:

$25

Explanation:

The computation of the intrinsic value of the stock is shown below:

As we know that

Intrinsic value or Price = Dividend ÷ (Cost of equity - growth rate)

where,

Cost of equity or ke is

= Risk free rate of return + beta × (Market rate of return - risk free rate of return)

= 6% + 0.75 × (14% - 6%)

= 12 %

So the intrinsic value is

= $1.50 ÷ (12% - 6%)

= $25

7 0

3 years ago

Read 2 more answers

What is the most violent star death called

gogolik [260]

Hi there!

The most violent star death is a Supernova. This is the massive explosion of a supergiant star as it's fuel source runs out and it can no longer fuse iron at its core safely. This causes the star to swell to unstable sizes until it explodes in a Supernova. The amount of energy that is output during a supernova is equivalent to all the energy our own Sun outputs in its whole lifetime.

6 0

4 years ago

The company where you work has obtained and stored five lasers in a supply room. You have been asked to determine the intensity

VikaD [51]

Answer:

a) I = 5.79 10⁵ W/m² , b) I = 2.58 10² W / m², c) I = 8.03 10³ W / m² , d) I = 5.3 10⁶ W / m², e) I = 9 10¹ W / m² , f) D> A> C> B> E

Explanation:

The intensity is defined as the power per unit area

I = P / A

The area of a circle is

A = π r²

Laser A

Power P = 2.2 W

Diameter d = 2.9 mm = 2.9 10⁻³ m

Let's calculate

Area

A = π d² / 4

A = π (2.2 10⁻³)²/4

A = 3.80 10⁻⁶ m²

Let's calculate the intensity

I = 2.2 / 3.80 10⁻⁶

I = 0.579 10⁶ W / m²

I = 5.79 10⁵ W/m²

Laser B

The electric field is E = 440 V / m

Intensity average is

I = E B / 2 μ₀

The relationship of the fields with the speed of light

E / B = c

The intensity

I = EE / 2 μ₀ c

I = 440² / (2 4π 10⁻⁷ 3 10⁸)

I = 1.936 105/750

I = 2.58 10² W / m²

Laser C

The magnetic field amplitude B = 8.2 10⁻⁶ T

I = c / 2μ₀ B²

I = 3 10⁸/2 4π 10⁻⁷ (8.2 10⁻⁶)²

I = 8.03 10³ W / m²

Part D

Diameter d = 1.8 mm = 1.8 10⁻³ m

The radius is r = d / 2 = 0.9 10⁻³ m

The force is F = 9.0 10⁻⁸ N

The radiation pressure is on a reflective surface is

P = 2S / c

I = S =P c / 2

The definition of pressure is

P = F / A

I = F c / 2 A

I = 9.0 10⁻⁸ 3 10⁸ / (2π (0.9 10⁻³)²)

I = 5.3 10⁶ W / m²

Part E

Average energy density

u = 3.0 10⁻⁷ J / m³

I = S = c u

I = 3 10⁸ 3.0 10⁻⁷

I = 9 10¹ W / m²

Part F

Sort in descending order

The order is

D> A> C> B> E

7 0

3 years ago