Mechanical waves propagate or move through a medium because

A body is placed on a rough inclined plane. Why does the frictional force decrease with the increase of angle of inclination

kondor19780726 [428]

The frictional force is directly proportional to the force that is perpendicular on the surface.

When the body is placed on a horizontal level with zero inclination, the only force acting on the body is the gravitational force which always pulls the body down. The gravitational force, in this case, is the perpendicular force to the surface. Accordingly, this entire force is used to generate friction

Now as the inclination of the surface increases, the gravitational force is no longer the perpendicular force of the body, its value decreases, which means only a part is used to generate frictional force. Consequently, frictional force decreases.

When the inclination reaches 90 degrees, the gravitational force does not act along the normal and accordingly, no friction force is generated.

7 0

2 years ago

When can a high speed velocity cause damage?'

sweet-ann [11.9K]

Answer:

50 Mph.

Explanation:

According to the National Severe Storms Laboratory, winds can really begin to cause damage when they reach 50 mph. But here’s what happens before and after they reach that threshold, according to the Beaufort Wind Scale (showing estimated wind speeds): - at 19 to 24 mph, smaller trees begin to sway.

7 0

2 years ago

The 3rd question i need answers

jeka94

Answer:

$\sf{B. Two \: quantities \: can \: have \: the \: same \: dimensions \: but \: different \: unit. }$

4 0

2 years ago

8. A rectangle is measured to be 6.4 +0.2 cm by 8.3 $0.2 cm.

mamaluj [8]

Answer:

a) The perimeter of the rectangle is 29.4 centimeters.

b) The uncertainty in its perimeter is 0.8 centimeters.

Explanation:

a) From Geometry we remember that the perimeter of the rectangle ( $p$ ), measured in centimeters, is represented by the following formula:

$p = 2\cdot (w+l)$ (1)

Where:

$w$ - Width, measured in centimeters.

$l$ - Length, measured in centimeters.

If we know that $w = 6.4\,cm$ and $l = 8.3\,cm$ , then the perimeter of the rectangle is:

$p = 2\cdot (6.4\,cm+8.3\,cm)$

$p = 29.4\,cm$

The perimeter of the rectangle is 29.4 centimeters.

b) The uncertainty of the perimeter ( $\Delta p$ ), measured in centimeters, is estimated by differences. That is:

$\Delta p = 2\cdot (\Delta w + \Delta l)$ (2)

Where:

$\Delta w$ - Uncertainty in width, measured in centimeters.

$\Delta l$ - Uncertainty in length, measured in centimeters.

If we know that $\Delta w = 0.2\,cm$ and $\Delta l = 0.2\,cm$ , then the uncertainty in perimeter is:

$\Delta p = 2\cdot (0.2\,cm+0.2\,cm)$

$\Delta p = 0.8\,cm$

The uncertainty in its perimeter is 0.8 centimeters.

5 0

2 years ago

The 630-nm light from a helium-neon laser irradiates a grating. The light then falls on a screen where the first bright spot is

dimaraw [331]

Answer:

464.8 nm

Explanation:

The second wavelength of light can be calculated using the next equation:

$\lambda = \frac{x*d}{L}$

Where:

λ : is the wavelength of light

x: is the distance from the central maximum

d: is the distance between the spots

L: is the lenght from the screen to the bright spot

For the first wavelength of light we have:

$\lambda_{1} = \frac{x_{1}*d}{L}$

$630 \cdot 10^{-9} m = \frac{0.61 m*d}{L}$

$\frac{d}{L} = \frac{630 \cdot 10^{-9} m}{0.61 m} = 1.033 \cdot 10^{-6}$ (1)

For the second wavelength of light we have:

$\lambda_{2} = \frac{x_{2}*d}{L}$

$\lambda_{2} = 0.45 m*\frac{d}{L}$ (2)

By entering equation (1) into equation (2) we have:

$\lambda_{2} = 0.45 m* 1.033 \cdot 10^{-6} = 4.648 \cdot 10^{-7} m = 464.8 nm$

Therefore, the second wavelength is 464.8 nm

I hope it helps you!

3 0

2 years ago