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4 years ago

WheN a car is driven some distance the air pressure in the tyre increases,why?

1 answer:

8 0

Over the course of a long drive, as a result of alternating between braking and acceleration and of course steering, tires get heated up. When this happens, the air within the tires gets heated up, causing the air within the tire to expand. This expanding air exerts force on the tire from inside thus increasing tire pressure.

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Mechanical (sound) waves to Earth from satellites. How is this possible? aves are unable to travel through a vacuum, such as thr

Anuta_ua [19.1K]

Sound waves are not able to travel in a vacuum, sound requires a medium such as air or a solid for example. Satellites are indeed in space, but radio waves are not sound waves they are a form of light. Light can travel in a vacuum so the messages that satellites beam back to Earth are light waves not sound waves, that is why it is possible.

6 0

3 years ago

A block is pulled across a flat surface at a constant speed using a force of 50 newtons at an angle of 60 degrees above the hori

vladimir2022 [97]

The magnitude of the friction force is 25 N

Explanation:

To solve this problem, we just have to analyze the forces acting on the block along the horizontal direction. We have:

The horizontal component of the pulling force, $F cos \theta$ , where F = 50 N is the magnitude and $\theta=60^{\circ}$ is the angle between the direction of the force and the horizontal; this force acts in the forward direction
The force of friction, $F_f$ , acting in the backward direction

According to Newton's second law, the net force acting on the block in the horizontal direction must be equal to the product between the mass of the block and its acceleration:

$\sum F_x = ma_x$

where

m is the mass of the block

$a_x$ is the horizontal acceleration

However, the block is moving at constant speed, so the acceleration is zero:

$a_x = 0$

So the equation becomes

$\sum F_x = 0$ (1)

The net force here is given by

$\sum F_x = F cos \theta - F_f$ (2)

And so, by combining (1) and (2), we find the magnitude of the friction force:

$F cos \theta - F_f = 0\\F_f = F cos \theta = (50)(cos 60^{\circ})=25 N$

Learn more about force of friction:

brainly.com/question/6217246

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#LearnwithBrainly

4 0

3 years ago

If you could shine a very powerful flashlight beam toward the Moon, estimate the diameter of the beam when it reaches the Moon.

grin007 [14]

To develop this problem it is necessary to apply the Rayleigh Criterion (Angular resolution)criterion. This conceptos describes the ability of any image-forming device such as an optical or radio telescope, a microscope, a camera, or an eye, to distinguish small details of an object, thereby making it a major determinant of image resolution. By definition is defined as:

$\theta = 1.22\frac{\lambda}{d}$

Where,

$\lambda$ = Wavelength

d = Width of the slit

$\theta$ = Angular resolution

Through the arc length we can find the radius, which would be given according to the length and angle previously described.

The radius of the beam on the moon is

$r = l\theta$

Relacing $\theta$

$r = l(\frac{1.22\lambda}{d})$

$r = 1.22\frac{l\lambda}{d}$

Replacing with our values we have that,

$r = 1.22*(\frac{(384*10^3km)(\frac{1000m}{1km})(550*10^{-9}m)}{7*10^{{-2}}})$

$r = 3680.91m$

Therefore the diameter of the beam on the moon is

$d = 2r$

$d = 2 * (3690.91)$

$d = 7361.8285m$

Hence, the diameter of the beam when it reaches the moon is 7361.82m

8 0

3 years ago

Which image shows the difference between the speed of molecules in hot and cold water? Explain your answer choice.

Leto [7]

There is no image btw

7 0

3 years ago

Read 2 more answers

A 60kg skateboarder starts up a 20° slope at 5m/s then falls and slides up the hill on his knee pads. The coefficient of kinetic

klasskru [66]

2.0 meters The skateboarder has 2 forces acting upon him to slow him down. The forces are friction, and climbing against the gravitational acceleration. So let's calculate the magnitude of these forces to see how fast he's decelerated. The coefficient of kinetic friction is a multiplier to use against the normal force of the object. We can calculate the normal force by multiplying the mass of the object by the local gravitational acceleration and the cosine of the angle. So Df = 60 kg * 9.8 m/s^2 * cos(20Â°) * 0.30 Df = 60 kg * 9.8 m/s^2 * 0.939692621 * 0.30 Df = 60 kg * 9.8 m/s^2 * 0.939692621 * 0.30 Df = 165.7617783 kg*m/s^2 Df = 165.7617783 N
The second amount of force is that caused by gravitational acceleration while climbing. That is determine by the amount of height gained for every meter along the slope. We can calculate that using the sine of the angle. So
Dg = 60 kg * 9.8 m/s^2 * sin(20Â°)
Dg = 60 kg * 9.8 m/s^2 * 0.342020143
Dg = 201.1078443 kg*m/s^2
Dg = 201.1078443 N

So the amount of force decelerating the skateboarder is:
F = Df + Dg
F = 165.7617783 N + 201.1078443 N
F = 366.8696226 N

Now let's determine how much kinetic energy needs to be dissipated. The equation is
E = 0.5 MV^2
So we'll substitute the known values and calculate
E = 0.5 MV^2
E = 0.5* 60 kg * (5 m/s)^2
E = 0.5* 60 kg * 25 m^2/s^2
E = 750 kg*m^2/s^2
E = 750 J
Now let's divide the energy by the force.
750 kg*m^2/s^2 / 366.8696226 kg*m/s^2 = 2.04432298 m
Rounding to 2 significant figures gives a distance of 2.0 meters.

4 0

3 years ago