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3 years ago

15

Why does the blue force have a negative sign?

1 answer:

dimaraw [331]3 years ago

8 0

it’s B (because 20 Is smaller than 50)

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Definition of fluoresence

denis23 [38]

Answer:

the property of absorbing light of short wavelength and emitting light of longer wavelength.

Explanation:

YW

4 0

3 years ago

Read 2 more answers

A ship maneuvers to within 2.50 x 10^3 m of an islands 1.80 x 10^3 m high mountain peak and fires a projectile at an enemy ship

Neporo4naja [7]

Answer:

Explanation:

Distance between ship and enemy ship

= 500 + 610

= 3110 m

Range of projectile

R = u² sin2θ / g

= (250x 250 sin 150) / 9.8

= 3188m

The projectile falls within a distance of 3188 - 3110 = 78 m from enemy ship

Height of mountain = 1800 m

We shall find the height of projectile when its horizontal displacement is 2500m

x = 2500 , y = ?

u = 2500 ,

y = x / cos θ - .5 g x² /u²cos² θ

$\frac{2500}{.2588} - \frac{.5 \times9.8\times2500\times2500}{250\times250\times.2588}$

9660 - 7315 m

= 2345 m

It is within 545 m from mountain peak .

8 0

3 years ago

The fastest time ever run at Pikes Peak is 7:57. That’s way too long. If we removed all the curves, making a straight line from

anygoal [31]

Answer: 271.4 s

Explanation:

We are told the top speed (maximum speed) $V_{max}$ the car has is:

$V_{max}=203 mph=90.74 m/s$ taking into account $1 mile=1609.34 m$

And the car's average acceleration $a_{ave}$ is:

$a_{ave}=0.091 g=2.93 ft/s^{2}=0.89 m/s^{2}$

Since:

$a_{ave}=\frac{V_{f}-V_{o}}{\Delta t}$ (1)

Where:

$V_{f}=V_{max}=90.74 m/s$ is the car's final speed (top speed)

$V_{o}=0 m/s$ because it starts from rest

$\Delta t$ is the time it takes to reach the top speed

Finding this time:

$\Delta t=\frac{V_{f}-V_{o}}{a_{ave}}$ (2)

$\Delta t=\frac{90.74 m/s - 0 m/s}{0.89 m/s^{2}}$ (3)

$\Delta t=t_{1}=101.95 s$ (4)

Now we have to find the distance $d$ the car traveled at this maximum speed with the following equation:

$V_{f}^{2}=V_{o}^{2} + 2a_{ave} d$ (5)

Isolating $d$ :

$d=\frac{V_{f}^{2}}{2a_{ave}}$ (6)

$d=\frac{(90.74 m/s)^{2}}{2(0.89 m/s^{2})}$ (7)

$d=4625.70 m$ (8)

On the other hand, we know the total distance $D$ traveled by the car is:

$D=12.42 miles = 19988.052 m$

Hence the remaining distance is:

$d_{remain}=D-d=19988.052 m - 4625.70 m$ (9)

$d_{remain}=15362.35 m$ (10)

So, we can calculate the time $t_{2}$ it took to this car to travel this remaining distance $d_{remain}$ at its top speed $V_{max}$ , with the following equation:

$V_{max}=\frac{d_{remain}}{t_{2}}$ (11)

Isolating $t_{2}$ :

$t_{2}=\frac{d_{remain}}{V_{max}}$ (12)

$t_{2}=\frac{15362.35 m}{90.74 m/s}$ (13)

$t_{2}=169.45 s$ (14)

With this time $t_{2}$ and the value of $t_{1}$ calculated in (4) we can finally calculate the total time $t_{TOTAL}$ :

$t_{TOTAL}=t_{1}+ t_{2}$ (15)

$t_{TOTAL}=101.95 s + 169.45 s$ (16)

$t_{TOTAL}=271.4 s s$

5 0

4 years ago

Does lightning McQueen have car or life insurance?

shutvik [7]

I am taking an educated guess that he has life insurance

7 0

3 years ago

A diver comes off a board with arms straight up and legs straight down, giving her a moment of inertia about her rotation axis o

mihalych1998 [28]

Answer:

θ₁ = 0.5 revolution

Explanation:

We will use the conservation of angular momentum as follows:

$L_1=L_2\\I_1\omega_1=I_2\omega_2$

where,

I₁ = initial moment of inertia = 18 kg.m²

I₂ = Final moment of inertia = 3.6 kg.m²

ω₁ = initial angular velocity = ?

ω₂ = Final Angular velocity = $\frac{\theta_2}{t_2} = \frac{2\ rev}{1.2\ s}$ = 1.67 rev/s

Therefore,

$(18\ kg.m^2)\omega_1 = (3.6\ kg.m^2)(1.67\ rev/s)\\\\\omega_1 = \frac{(3.6\ kg.m^2)(1.67\ rev/s)}{(18\ kg.m^2)}\\\\\omega_1 = \frac{\theta_1}{t_1} = 0.333\ rev/s\\\\\theta_1 = (0.333\ rev/s)t_1$

where,

θ₁ = revolutions if she had not tucked at all = ?

t₁ = time = 1.5 s

Therefore,

$\theta_1 = (0.333\ rev/s)(1.5\ s)\\$

<u>θ₁ = 0.5 revolution</u>

4 0

3 years ago