Question 19 of 20
8 44%
Look at the diagram. To overcome the friction force, the man could use a slippery
substance like oil or graphite spray on the floor. These substances are examples of
what?
Enter your answer

Answer:

i believe atomic mass

Explanation:

Answer:-37.5 m/s

Explanation:

Answer:

-37.5

Explanation:

Answer:

3.

Force(f) =2000N

Distance (d) =10m

Time(t)=50 sec

We know,

P=W/t

=f×d/t

=2000×10/50

=400 watt

4.

Force(f) =30N

Distance (d) =10 m

Time(t) =5 sec

We know,

P=w/t

=f×d/t

=30×10/5

=60 watt

Answer:

c

Explanation:

c. the ability to do work or to produce heat

Answer:

When frequency increases more wave crests pass a fixed point each second. That means the wavelength shortens. So, as frequency increases, wavelength decreases. The opposite is also true—as frequency decreases, wavelength increases.

Answer:

B) boiling point

Explanation:

The movement of the particles causes the shape of the liquid to change. The liquid will flow and fill to the lowest part of the container, in the shape of the container

But the volume does not change. The limited amount of space between the particles means that the liquid has only very limited compressibility.

Answer:

A) Density

Explanation:

Answer:

8n

Explanation:

Answer:

b

Explanation:

i guessed annd got it right

Answer:

Reaction B involves a greater change and a change in element identity.

Explanation:

Answer:

The air temperature at the tropopause is - 79 °C

Explanation:

We know that a station near the equator has a surface temperature of 25°C

Vertical soundings reveal an environmental lapse rate of 6.5 °C per kilometer.

The tropopause is encountered at 16 km.

In order to find the air temperature at the tropopause we are going to deduce a linear function for the temperature at the tropopause.

This linear function will have the following structure :

[tex]f(x)=ax+b[/tex]

Where ''[tex]a[/tex]'' and ''[tex]b[/tex]'' are real numbers.

Let's write [tex]T(x)[/tex] to denote the temperature '' T '' in function of the distance

'' x '' ⇒

[tex]T(x)=ax+b[/tex]

We can reorder the function as :

[tex]T(x)=b+ax[/tex] (I)

Now, at the surface the value of ''[tex]x[/tex]'' is 0 km and the temperature is 25°C so in the function (I) we write :

[tex]T(0)=25=b+a(0)[/tex] ⇒ [tex]b=25[/tex] ⇒

[tex]T(x)=25+ax[/tex] (II)

In (II) the value of ''[tex]a[/tex]'' represents the change in temperature per kilometer.

Because the temperature decrease with the height this number will be negative and also a data from the question ⇒

[tex]T(x)=25-(6.5)x[/tex] (III)

In (III) we deduced the linear equation. The last step is to replace by [tex]x=16[/tex] in (III) ⇒

[tex]T(16)=25-(6.5)(16)=-79[/tex]

The air temperature at the tropopause is - 79 °C

Answer:

1. s = d/t

22. d = 3km = 3000m

t = 2m = 60s

s = 3000/60

= 300/6

= 50m/s

Therefore, the speed of the car is 50 m/s.

23. s = 60km/hr

t = 2hrs

d = s × t

d = 60 × 2

d = 120km

The car travels for 120km.

24. s = 10mile/hr

d = 35km

t = d/s

t = 35/10

t = 3.5hrs

The girl takes 3.5 hours to cover the distance

4000 ÷ 8 = 500

Its 500 m/s as shown in the calculation above.

Answer:

Forty-eight million eight hundred thousand

Explanation:

You divide 585.6/12. I really hope this helps!!

Answer:

35.16 degrees

Explanation:

Knowing that the index of refraction of the guide is 1.33, calculate the resulting angle of refraction for a ray of light that falls on a pool with an angle of incidence of 50º

Refractive index, n = 1.33

The angle of incidence, i = 50°

We need to find the angle of refraction. let it is r. It can be calculated using Snells law as follows:

[tex]n=\dfrac{\sin i}{\sin r}\\\\\sin r=\dfrac{\sin i}{n}\\\\r=\sin^{-1}(\dfrac{\sin i}{n})\\\\r=\sin^{-1}(\dfrac{\sin 50}{1.33})\\\\r=35.16^{\circ}[/tex]

So, the angle of refraction is 35.16 degrees.

Answer:

Two non-perpendicular vectors will not form a right triangle. Yet it is possible to force two (or more) non-perpendicular vectors to be transformed into other vectors that do form a right triangle. The trick involves the concept of a vector component and the process of vector resolution.

Answer:

Because it comprises both physical and mental activities.

Explanation:

Orienteering is a sport that is known for its physical and mental activities. It is an ideal sport for the most promotion of physical activity and lifetime sports because it involves moving through the wild or difficult terrain. This takes energy to be competitive, and it also requires participants to take challenging decisions now and then.

People of different ages can participate and allows them to apply real-world decision-making skills to the competition. It also gives participants the chance to learn about themselves more and how to face different situations.

Answer:

I have no clue sorry I wish I could help

If an element forms a 3+ ion, one can expect to find it in group 13 of the periodic table (option C).

Periodic table is a tabular chart of the chemical elements according to their atomic numbers so that elements with similar properties are in the same group (column).

The periodic table is made up of vertical columns called group and horizontal rows called periods.

Elements in group 13 form ions with +3 and +1 charges. The elements are as follows:

Therefore, group 13 elements in the periodic table form +³ ions.

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Answer:

a)  y_total = 575.4 m , b)   t_total = 22.56 s , c)  v = 106.20 m

Explanation:

a) We can solve this exercise using the scientific relations

Let's find the height reached while the engines are running

         v₁ = v₀ + a t

         v₁ = 62.3 + 4.30 3.73

         v₁ = 78.339 m / s

in this time it rose

        y₁ = v₀ t₁ + ½ a t₁²

        y₁ = 62.3 3.73 + ½ 4.30 3.73²

         y₁ = 262.29 m

At this moment the engines are turned off and the rocket continues in a vertical launch, suppose that the acceleration of gravity is constant in this path

        v₂ = v₁ 2 - 2 g y₂

at maximum height the velocity is zero (v₂ = 0)

        y₂ = v₁ 2 / 2g

        y₂ = 78.339 2/2 9.8

        y₂ = 313.11 m

the total height is

       y_total = y₁ + y₂

       y_total = 262.29 + 313.11

       y_total = 575.4 m

b) the time the rocket is in the air is

       t_total = t₁ + t₂

where t₂ is the time after the engines have shut down

       y = y₁ + v₁ t₂ - ½ g t₂²

      y = 0

      0 = 262.29 + 78.339 t₂ - ½ 9.8 t₂²

      t₂² - 15.99 t₂ - 53.53 = 0

      t₂ = [15.99 ±√ (15.99² +4  53.53)] / 2

      t₂ = [15.99 ± 21.67] / 2

      t₂´ = 18.83 s

      t₂´´ = -2.84 s

since the time must be a positive quantity the correct result is t2 = 18.83 s, the total time in the air is

      t_total = 3.73 + 18.83

      t_total = 22.56 s

c) the speed when it hits the ground

We can perform this calculation starting with the maximum height y = 575.4 m where it has zero initial velocity (vo = 0)

      v² = v₀² + 2 g y

      v = √ 2gy

       v = √ (2 9.8 575.4)

       v = 106.20 m

Answer:

U = 18,785 J

Explanation:

Elastic Energy

Elastic energy is energy stored in an object due to a force that temporarily changes its shape, such as shrinking or stretching.

The elastic energy can be calculated as follows:

[tex]\displaystyle U=\frac{1}{2}k(\Delta x)^2[/tex]

Where k is the spring constant, and \Delta x is the change in the size of the spring.

The bungee cord stretches \Delta x =17 m, and k=130 N/m, thus:

[tex]\displaystyle U=\frac{1}{2}130(17)^2[/tex]

U = 18,785 J

Answer:

If a particle is affected by a wave, then the particles are displaced. They move along the direction of the wave. Hence, After a wave passes through a medium, particles in the medium are moved along with the wave.

Explanation:

hope this helps you

Answer:

1) Yes, the gazelle gets to safety

2) The speed with which the gazelle needs to run, to beat the cheater by 2 seconds is approximately 29.79 m/s

Explanation:

1) The distance of the gazelle, from the gazelle safe zone = 275 m

The distance of the cheetah from the gazelle = 455 m

The speed of the gazelle = 25 m/s

The speed of the cheetah = 65 m/s

Therefore, we have;

Let the time the gazelle reaches the safe zone = t, which gives;

t = 275 m/(25 m/s) = 11

t = 11 seconds

Let the time the cheetah reaches the gazelle = t₁, we have;

455 + 25 × t₁ = 65 × t₁

t₁ = 455/40 = 11.375

t₁ = 11.375 seconds

The gazelle reaches the gazelle safe zone before the cheetah reaches the gazelle

Therefore, the gazelle gets to safety

2) In order for the gazelle to beat the gazelle by 2 seconds, we have;

The time for the cheetah to reach the safe zone = (275 + 455)/65 = 11.23 seconds

Therefore, we have;

In order for the gazelle to beat the gazelle by 2 seconds the time the cheetah reaches the safe zone = 11.23 - 2 = 9.23 s

The speed of the gazelle is then 275/9.23 ≈ 29.79 m/s

Answer: d = r · t d + 300cheertah = 18t gazelle = 16t the running times are equal!   (d + 300) / 18 = d / 16   Solve ford then determine time.

sorry if its confusing

Answer: 519.4 N

Explanation:

53 kg x 9.8 m/s = 519.4 N

If a 53 kg Boulder falls off a cliff, the force with which it will hit the ground is 519.4 N.

A force is an effect that can alter an object's motion according to physics. An object with mass can change its velocity, or accelerate, as a result of a force. An obvious way to describe force is as a push or a pull. A force is a vector quantity since it has both magnitude and direction.

Given in the question  a 53 kg Boulder falls off a cliff, what is the force with which it will hit the ground,

force = mass * acceleration due to gravity

         = 53 kg x 9.8 m/s

         = 519.4 N

If a 53 kg Boulder falls off a cliff, the force with which it will hit the ground is 519.4 N.

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Answer:

69.28N

Explanation:

horizontal force

Cos 60°= F(horizontal)/80N

If we cross multiply, we have

F(horizontal)= 80 cos 60°

= 40N

vertical forces

Sin 60°= F(vertical)/80N

If we cross multiply we have

F( vertical) = 80 sin 60°

= 69.28N

Therefore, the vertical force is 69.28N

Answer:

I = 2 [amp]

Explanation:

To solve this problem we must use ohm's law, which tells us that the voltage is equal to the product of the current by the resistance.

The resistances in the diagram are connected in series, in this way the total resistance will be equal to the algebraic sum of the resistivity.

R = R1 + R2

R = 3 + 2

R = 5 [ohm]

Now, using ohm's law we have:

V = I*R

where:

V = voltage = 10 [V]

I = current [amp]

R = resistance = 5 [ohm]

I = V/R

I = 10/5

I = 2 [amp]

Answer:33s

Explanation:

Answer: 3.3 seconds

Explanation:

I just did it

Potential energy = m · g · h

-- When you held the ball at 2.0 meters above the floor, it had

(0.5 kg) · (9.8 m/s²) · (2.0 m) = 9.8 Joules of potential energy.

-- After it bounced and went back up as high as it could, it was only 1.8 meters above the floor.  Its potential energy was

(0.5 kg) · (9.8 m/s²) · (1.8 m) = 8.82 Joules

-- Between the drop and the top of the bounce, it lost

(9.8 - 8.82) = 0.98 Joule .

-- The energy was lost when the ball hit the floor.  During the hit, 0.98 joule of kinetic energy turned to thermal energy, which slightly heated the ball and the floor.

Answer:

D

Explanation:

Answer:

Reaction is 20N.

Explanation:

In general, Newton's third law of motion explains that when a force is applied on an object, a reaction of equal magnitude applies in the reverse direction of the force.

i.e F = -R

This implies that, reaction is a force in the opposite direction to that of the force applied.

Force can also be related to the weight of an object as;

F = W = mg

Thus to prevent the 20N stone from falling, a force of 20N is applied in the opposite direction. So the reaction, R is 20N.