Suppose you increase your walking speed from 7 m/s to 11 m/s in a period of 1 s. What is your acceleration?

A wave of wavelength 0.3 m travels 900 m in 3.0 s. Calculate its frequency.

zzz [600]

Answer:

1000 Hz

Explanation:

The frequency would be 1000 Hz.

The frequency, wavelength, and speed of a wave are related by the equation:

v = fλ ..................(1)

where v = speed of the wave, f = frequency of the wave, and λ = wavelength of the wave.

Making f the subject of the formula:

f = v/λ.........................(2)

Also, speed (v) = distance/time.

From the question, distance = 900 m, time = 3.0 s

Hence, v = 900/3.0 = 300 m/s

Substitute v = 300 and λ = 0.3 into equation (2):

f = 300/0.3 = 1000 Hz

6 0

2 years ago

a body weights 28N at a height of 3200km from the earth surface.What will be the gravitational force on that body if its lies on

alekssr [168]

Answer:

The object would weight 63 N on the Earth surface

Explanation:

We can use the general expression for the gravitational force between two objects to solve this problem, considering that in both cases, the mass of the Earth is the same. Notice as well that we know the gravitational force (weight) of the object at 3200 km from the Earth surface, which is (3200 + 6400 = 9600 km) from the center of the Earth:

$F_G=G\,\frac{M_E\,m}{d^2} \\28\,\,N=G\,\frac{M_E\,m}{9600000^2}$

Now, if the body is on the surface of the Earth, its weight (w) would be:

$F_G=G\,\frac{M_E\,m}{d^2} \\w=G\,\frac{M_E\,m}{6400000^2}$

Now we can divide term by term the two equations above, to cancel out common factors and end up with a simple proportion:

$\frac{w}{28} =\frac{9600000^2}{6400000^2} \\\frac{w}{28} =\frac{9}{4} \\\\ \\w=\frac{9\,*\,28}{4}\,\,\,N\\w=63\,\,N \\$

4 0

3 years ago

Aluminum and copper are good ____ because they don't have a strong hold on valence electrons. * a. Insulators b. Transistors c.

SOVA2 [1]

aluminum and copper are C.) conductors

6 0

3 years ago

A meter stick A hurtles through space at a speed v = 0.25c relative to you, with its length aligned with the direction of motion

yaroslaw [1]

Answer:

$L_0\approx1.0328\ m$

Explanation:

Given:

relativistic length of stick A, $L=1\ m$

relativistic velocity of stick A with respect to observer, $v=0.25c=7.5\times 10^{7}\ m.s^{-1}$

Since the object is moving with a velocity comparable to the velocity of light with respect to the observer therefore the length will appear shorter according to the theory of relativity.

Mathematical expression of the theory of relativity for length contraction:

$L=\frac{L_0}{\gamma}$