All categories

3 years ago

A bird can fly 25 km/h. How long does it take to fly 3.5km?

1 answer:

7 0

Speed of bird = 25km / h, it means a bird covers a distance of 25 km in 1 hour or 60 minutes.
A birds covers a distance of 1 km in time = 1 hour = 60 min
so, 60 / 25 = 2.4 = 2 minutes 4 second
it means a bird covers a distance of 1 km in 2 minutes 4 second, so a bird take time to fly 3.5 km in time = 3.5 x 2.4 = 8.4 = 8 minutes 4 second
So, the answer is 8 minutes 4 seconds.

You might be interested in

A sound wave has a frequency of 250 Hz and a wavelength of 2.5 m. What is the speed of the wave?

Digiron [165]

ANSWER

625 m/s

EXPLANATION

Given:

• The frequency of the sound wave, f = 250 Hz

• The wavelength, λ = 2.5 m

Find:

• The speed of the wave, v

The speed of a wave of wavelength λ and frequency f is given by,

$v=f\cdot\lambda$

Substitute the known values and solve,

$v=250Hz\cdot2.5m=625m/s$

Hence, the speed of the wave is 625 m/s.

3 0

1 year ago

26. The equation E=hf describes the energy of each photon in a beam of light. If Planck’s constant, h, were larger, would photon

Elenna [48]

The equation of the energy of a photon is E=h*f.

If we increase the Planck's constant h, the energy would increase.

For example, lets double the value of Planck's constant and name it H:

H=2*h. Now lets put that into the equation for energy that we will call E₂:

E₂=H*f=2*h*f=2*E.

So we can clearly see that E₂=2*E or that if we double Planck's constant, the energy also doubles.

6 0

3 years ago

The graph below represents the relationship between speed and time for an object moving along a straight line. What is the total

KiRa [710]

The distance travelled by the object during the first 4 seconds is 80 m

<h3>Definition of speed </h3>

Speed is defined as the distance travelled per unit time. Mathematically, it can be expressed as:

Speed = distance / time

With the above formula, we can obtain the distance travelled by the object in the first 4 seconds.

<h3>How to determine the distance travelled </h3>

Speed = 20 m/s
Time = 4 s

Distance =?

Speed = distance / time

20 = distance / 4

Cross multiply

Distance = 20 × 4

Distance = 80 m

Complete question:

See attached photo

Learn more about speed:

brainly.com/question/680492

4 0

2 years ago

Si el coeficiente de fricción cinética entre los neumáticos y el pavimento seco es de 0.80. ¿Cuál es la distancia mínima para de

vovangra [49]

Answer: 52.9 metros.

Explanation:

Podemos escribir la fuerza de fricción cinética como

F = μ*N

donde N es la fuerza normal entre el coche y el suelo, cuya magnitud es igual al peso en esta situación.

F = μ*m*g

donde m es la masa del coche y g es 9.8m/s^2

y sabemos que μ = 0.8

Por la segunda ley de Newton, sabemos que:

F = m*a

fuerza es igual a masa por aceleración.

a = F/m

entonces la aceleración causada por la fuerza de rozamiento es:

F = 0.8*m*g

a = F/m = (0.8*m*g)/m = 0.8*g.

Entonces ya encontramos la aceleración, hay que recordar que esta aceleración es en sentido opuesto a la sentido de movimiento, entonces podemos escribir la aceleración como:

a(t) = -0.8*g

Para la velocidad, podemos integrar sobre el tiempo para obtener.

v(t) = -0.8*g*t + v0

donde v0 es la velocidad inicial del auto = 28.7m/s

v(t) = -0.8*g*t + 28.8m/s

Ahora podemos encontrar el tiempo necesario para que la velocidad del coche sea cero, en ese momento, como deja de moverse, ya no tendremos rozamiento cinético, entonces no habrá aceleración y el coche se detendrá completamente.

v(t) = 0m/s = -0.8*9.8m/s^2*t + 28.8m/s

7.84m/s^2*t = 28.8m/s

t = (28.8m/s)/(7.84m/s^2) = 3.63 segundos.

Ahora vamos a la ecuación de movimiento, donde asumimos que la posición inicial del coche es 0m, así que no tendremos constante de integración.

p(t) = -(1/2)*(0.8*9.8m/s^2)*t^2 + 28.8m/s*t

Ahora podemos evaluar la posición en t = 3.63 segundos, y esto nos dara la distancia que el coche se movio mientras frenaba.

p(3.63s) = -(1/2)*(0.8*9.8m/s^2)*(3.63s)^2 + 28.8m/s*(3.63s) = 52.9 metros.

6 0

3 years ago

You push against a steamer trunk with a force of 800 n at an angle alpha with the horizontal . the trunk is on a flat floor and

galina1969 [7]

The formula for this problem that we will be using is:
F * cos α = m * g * μs where:F = 800m = 87g = 9.8
cos α = m*g*μs/F= 87*9.8*0.55/800= 0.59 So solving the alpha, find the arccos above.
α = arccos 0.59 = 54 ° is the largest value of alpha

6 0

3 years ago