You can hear someone around the corner before you can see them due to reflection, diffraction, refraction, or absorption?

If the Speed limit is 60 mph, if I drive at a speed of 130 km/hr would I maybe get a ticket? (0.621 mi = 1km)

katovenus [111]

Explanation:

130km = (0.621 * 130) mi = 80.73 mi

So if you drive at 80.73 mph you will get a ticket for speeding over the limit.

5 0

2 years ago

Suppose that a public address system emits sound uniformly in all directions and that there are no reflections. The intensity at

dybincka [34]

Answer:

The intensity at a spot 71 m away is $4.02*10^{-5} Wm^{-2}$

Explanation:

Given:

Initial intensity, $I_{1}=3.0*10^{-4} Wm^{-2}$ at a distance, $d_{1} = 26 m$

Required:

New intensity, $I_{2} =?$ at a distance, $d_{2} = 71 m$

Using the inverse square law,

I ∝ $\frac{1}{d^{2} }$

⇒ $I_{1}$ $I_{1}d_{1}^{2} =I_{2}d_{2}^{2}$

$I_{2} =\frac{I_{1} d_{1}^{2} }{d_{2}^{2}} =\frac{3.0*10^{-4}*26^{2} }{71^{2} } \\$ ×

$I_{2}=4.02*10^{-5} Wm^{-2}$

Thus, the intensity at a spot that is 71 m away is $4.02*10^{-5} Wm^{-2}$

5 0

2 years ago

Nichrome is used as heating element in heater.Why?

Masja [62]

Nichrome is a mixture of nickel and chromium. Nichrome Wire is highly resistant to the flow of electricity . This resistance causes an increase in generated heat . It also has the ability to be heated many times without being destroyed. It is is a mixture of nickel and chromium.This heat is powerful enough to heat the water without damaging the wire.

7 0

2 years ago

A projectile is fired from ground level at time t=0, at an angle θ with respect to the horizontal. It has an initial speed v0 As

lina2011 [118]

Answer:

(a) Time to reach maximum height, $t_{H} =\frac{v_{0}\sin\theta }{g}$

(b) Time to reach the ground, $t_{R} =2t_{H} =\frac{2v_{0}\sin\theta }{g}$

(c) Maximum height, $H=\frac{(v_{0}\sin\theta) ^{2} }{2g}$

(d) Total horizontal distance, $R=\frac{v_{0} ^{2}\sin2\theta }{g}$

Explanation:

According to the problem, v₀ is initial speed, g is acceleration due to gravity and θ is angle with respect to the horizontal.

The horizontal and vertical components of the initial speed are v₀cosθ and v₀sinθ respectively.

There is no acceleration acting horizontally on the projectile but there is vertical acceleration g is acting on the projectile.

(a) The equation of motion along vertical direction is:

v = v₀sinθ - gt

At maximum height, the speed of projectile is zero i.e.v is zero in the above equation. Thus, the above equation becomes :

$0=v_{0}\sin\theta-gt_{H}$

$t_{H} =\frac{v_{0}\sin\theta }{g}$

(b) The time at which projectile hits the ground is :

$t_{R} =2t_{H} =\frac{2v_{0}\sin\theta }{g}$ ....(1)

(c) The equation of motion along vertical direction is :

v² = (v₀sinθ)² - 2gs

Here s is the vertical height of the projectile.

At maximum height H, v is zero. So, the above equation becomes :

$0=(v_{0}\sin\theta) ^{2}-2gH$

$H=\frac{(v_{0}\sin\theta) ^{2} }{2g}$

(d) The equation of motion along horizontal is :

x = (v₀cosθ)t

Here x is horizontal distance travel by projectile.

The total distance (R) traveled by projectile is :

$R=(v_{0}\cos\theta)t_{R}$

Substitute the equation (1) in above equation.

$R=\frac{2v_{0} ^{2} \sin\theta\cos\theta}{g}$

Using trigonometry relation:

2sinθcosθ = sin2θ

$R=\frac{v_{0} ^{2}\sin2\theta }{g}$

8 0

2 years ago

Un avioncito de control remoto viaja con una velocidad constante de 20 km/hr el tiempo en que se realiza el vuelo es de 25 minut

rosijanka [135]

Answer:

Distancia = 27559.06 pies

Explanation:

Dados los siguientes datos;

Velocidad = 20 km/hr

Tiempo = 25 minutos

Conversión de minutos a horas;

60 minutos = 1 hora

25 minutos = 0.42 horas

Para encontrar la distancia;

Distancia = velocidad * tiempo

Distancia = 20 * 0.42

Distancia = 8.4 km

Conversión de kilómetros a pies;

1 km = 3280.84 pies

8.4 kilometros = 8.4 * 3280,84 = 27559,06

Distancia = 27559.06 pies

5 0

2 years ago