Which two options are examples of waves reflecting?

A 20.0-N weight slides down a rough inclined plane which makes an angle of 30 degree with the horizontal. The weight starts from

Ulleksa [173]

Answer:

$1270.64\ \text{J}$

Explanation:

m = Mass of object = $\dfrac{mg}{g}$

mg = Weight of object = 20 N

g = Acceleration due to gravity = $9.81\ \text{m/s}^2$

v = Final velocity = 15 m/s

u = Initial velocity = 0

d = Distance moved by the object = 150 m

$\theta$ = Angle of slope = $30^{\circ}$

f = Force of friction

fd = Work done against friction

The force balance of the system is

$\dfrac{1}{2}m(v^2-u^2)=(mg\sin\theta-f)d\\\Rightarrow \dfrac{1}{2}mv^2=mg\sin\theta d-fd\\\Rightarrow fd=mg\sin\theta d-\dfrac{1}{2}mv^2\\\Rightarrow fd=20\times \sin 30^{\circ}\times 150-\dfrac{1}{2}\times \dfrac{20}{9.81}\times 15^2\\\Rightarrow fd=1270.64\ \text{J}$

The work done against friction is $1270.64\ \text{J}$ .

8 0

3 years ago

On your first trip to Planet X you happen to take along a 180 g mass, a 40-cm-long spring, a meter stick, and a stopwatch. You'r

lys-0071 [83]

Answer:

g_x = 3.0 m / s^2

Explanation:

Given:

- Change in length of spring [email protected] = 22.6 cm

- Time taken for 11 oscillations t = 19.0 s

Find:

- The value of gravitational free fall g_x at plant X:

Solution:

- We will assume a simple harmonic motion of the mass for which Time is:

T = 2*pi*sqrt(k / m ) ...... 1

- Sum of forces in vertical direction @equilibrium is zero:

F_net = k*x - m*g_x = 0

(k / m) = (g_x / x) .... 2

- substitute Eq 2 into Eq 1:

2*pi / T = sqrt ( g_x / x )

g_x = (2*pi / T )^2 * x

- Evaluate g_x:

g_x = (2*pi / (19 / 11) )^2 * 0.226

g_x = 3.0 m / s^2

3 0

3 years ago

The drawing below shows two different types of pulley systems designed to lift a weight. In pulley system A, the end of the rope

nadya68 [22]

The answer would be in the chart or graph A is 1 B is 2

4 0

3 years ago

Read 2 more answers

Which of the following statements is true about earth's magnetic poles

Dahasolnce [82]

Answer: b) they are the areas where Earth's magnetic field is weakest

Explanation:

According to classical physics, a magnetic field always has two associated magnetic poles (north and south), the same happens with magnets. This is because for <em>classical physics</em>, naturally, magnetic monopoles can not exist.

In this context, Earth is similar to a magnetic bar with a north pole and a south pole. This means, the axis that crosses the Earth from pole to pole is like a big magnet.

Now, by convention, on all magnets the north pole is where the magnetic lines of force leave the magnet and the south pole is where the magnetic lines of force enter the magnet. Then, for the case of the Earth, the north pole of the magnet is located towards the geographic south pole and the south pole of the magnet is near the geographic north pole.

Being the magnetic poles the places where the Earth's magnetic field is weakest. And it is for this reason, moreover, that the magnetic field lines enter the Earth through its magnetic south pole (which is the geographic north pole).

4 0

3 years ago

A rectangular field is 300 meters long and 300 meters wide. What is the area of the field in square kilometers? Do not round you

dexar [7]

Answer:

Area of the rectangular field in kilometers is 0.09 $km^2$

Explanation:

We know that 1 kilometers = 1000 meters

since we need to find the area in unit of kilometers

therefore converting length and width into kilometers

1000 meters = 1 kilometers

300 meters = $\frac{300}{1000} = 0.3$

Likewise width = 0.3 km

Area = length x width

= 0.3km x 0.3 km

= 0.09 $km^2$

6 0

3 years ago