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2 years ago

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You drive a beat-up pickup truck along a straight road for 8.4 km at 70 km/h, at which point the truck runs out of gasoline and

stops. Over the next 30 min, you walk another 2.0 km farther along the road to a gasoline station. What is your average velocity from the beginning of your drive to your arrival at the gasoline station?

2 answers:

andreev551 [17]2 years ago

6 0

Answer:

v_avg = 37 km/h

Explanation:

To find the average velocity in the complete trajectory you use the following formula:

$v_{avg}=\frac{v_1+v_2}{2}$ ( 1 )

v1: velocity in the first part of the trajectory = 70 km/h

v2: velocity in the second part of the trajectory = ?

You calculate v2 by using the following equation for a motion with constant velocity:

$v_2=\frac{2.0km}{30min}*\frac{60min}{1h}=4\frac{km}{h}$

you replace the values of v1 and v2 in (1) and you obtain:

$v_{avg}=\frac{70km/h+4km/h}{2}=37\frac{km}{h}$

hence, the average velocity is 37 km/h

kkurt [141]2 years ago

3 0

Answer:

v = 16.8 km/h

Explanation:

The average velocity can be calculated usign the following equation:

$v = \frac{\Delta x}{\Delta t}$

<u>Where</u>:

Δx: is the change in the displacement

Δt: is the change in the time

The total displacement is:

$x_{t} = 8.4 km + 2.0 km = 10.4 km$

The initial time is:

$t = \frac{x}{v} = \frac{8.4 km}{70 km/h} = 0.12 h$

The total time is:

$t_{t} = 0.12 h + 30min*\frac{1 h}{60 min} = 0.62 h$

Finally, by taking:

Δt = 0.62 h

Δx= 10.4 km

The average velocity is:

$v = \frac{10.4 km}{0.62 h} = 16.8 km/h$

Therefore, the average velocity is 16.8 km/h.

I hope it helps you!

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A wave traveling in the positive x-direction with a frequency of 50.0 Hz is shown in the figure below. Find the following values

Klio2033 [76]

Answer:

Explanation:

a. The amplitude is the measure of the height of the wave from the midline to the top of the wave or the midline to the bottom of the wave (called crests). The midline then divides the whole height in half. Thus, the amplitude of this wave is 9.0 cm.

b. Wavelength is measured from the highest point of one wave to the highest point of the next wave (or from the lowest point of one wave to the lowest point of the next wave, since they are the same). The wavelength of this wave then is 20.0 cm. or $\lambda=20.0cm$

c. The period, or T, of a wave is found in the equation

$f=\frac{1}{T}$ were f is the frequency of the wave. We were given the frequency, so we plug that in and solve for T:

$50.0=\frac{1}{T}$ so

$T=\frac{1}{50.0}$ and

T = .0200 seconds to the correct number of sig fig's (50.0 has 3 sig fig's in it)

d. The speed of the wave is found in the equation

$f=\frac{v}{\lambda}$ and since we already have the frequency and we solved for the wavelength already, filling in:

$50.0=\frac{v}{20.0}$ and

v = 50.0(20.0) so

v = 1.00 × 10³ m/s

And there you go!

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2 years ago

A major difference between radio waves, visible light, and gamma rays is the ____ of the photons, which results in the different

olga2289 [7]

The sentence can be completed as follows:
"<span>A major difference between radio waves, visible light, and gamma rays is the energy of the photons, which results in the different photon frequencies and wavelengths."

In fact, gamma rays have greater energy than visible light and visible light has greater energy than radio waves. The energy E of a photon is related to its frequency, f, by
</span> $E=hf$
<span>where h is the Planck constant. We see from this formula that the higher the frequency, the greater the energy. Instead, the wavelength is inversely proportional to the frequency:
</span> $\lambda= \frac{c}{f}$
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2 years ago

Read 2 more answers

When a vehicle travels at a steady speed the driving force and the

Ivanshal [37]

Answer:

.......

Must be equal

Explanation:

..

3 0

2 years ago

To pull an old stump out of the ground, you and a friend tie two ropes to the stump. You pull on it with a force of 500 N to the

zhannawk [14.2K]

Answer:

C. less than 950 N.

Explanation:

Given that

Force in north direction F₁ = 500 N

Force in the northwest F₂ = 450 N

Lets take resultant force R

The angle between force = θ

θ = 45°

The resultant force R

$R=\sqrt{F_1^2+F_2^2+2F_1F_2cos\theta}$

$R=\sqrt{500^2+450^2+2\times 450\times 500\times cos\theta}$

R= 877.89 N

Therefore resultant force is less than 950 N.

C. less than 950 N

Note- When these two force will act in the same direction then the resultant force will be 950 N.

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2 years ago

I am struggling on this physics question. Brainly is my last hope. Could somebody please provide an answer to this question, wit

Aleks [24]

1) 29.4 N

The force of gravity between two objects is given by:

$F=G\frac{Mm}{r^2}$

where

G is the gravitational constant

M and m are the masses of the two objects

r is the separation between the centres of mass of the two objects

In this problem, we have

$M=5.97\cdot 10^{24} kg$ (mass of the Earth)

$m=3.0 kg$ (mass of the box)

$r=R=6.37\cdot 10^6 m$ (Earth's radius, which is also the distance between the centres of mass of the two objects, since the box is located at Earth's surface)

Substituting into the equation, we find F:

$F=\frac{(6.67\cdot 10^{-11})(5.97\cdot 10^{24})(3.0)}{(6.37\cdot 10^6)^2}=29.4 N$

2) $g=9.8 m/s^2$

Let's now calculate the ratio F/m. We have:

F = 29.4 N

m = 3.0 kg

Subsituting, we find

$\frac{F}{m}=\frac{29.4}{3.0}=9.8 N/kg = 9.8 m/s^2$

This is called acceleration of gravity, and it is the acceleration at which every object falls near the Earth's surface. It is indicated with the symbol $g$ .

We can prove that this is the acceleration of the object: in fact, according to Newton's second law,

$F=ma$

where a is the acceleration of the object. Re-arranging,

$a=\frac{F}{m}$

which is exactly equal to the quantity we have calculated above.

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2 years ago