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2 years ago

A fast Humvee drove from desert A to desert B. For the first 12

Physics

1 answer:

Zina [86]2 years ago

4 0

Answer:

v = 172 km/h

Explanation:

For the first 12 hours, it traveled at an average speed of 185 km/h. Let d₁ is distance. So,

$d_1=v_1\times t_1\\\\d_1=185\ km/h\times 12\ h\\\\d_1=2220\ km$

For the next 13 hours, it traveled at an average speed of 160 km/h. Let d₂ is the distance. So,

$d_2=v_2\times t_2\\\\d_2=160\ km/h\times 13\ h\\\\d_2=2080\ km$

Average speed = total distance/time taken

So,

$v=\dfrac{d_1+d_2}{t_1+t_2}\\\\v=\dfrac{2220+2080}{12+13}\\\\v=172\ km/h$

So, the average speed of the whole journey is 172 km/h.

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Volcanoes are often formed at plate boundaries. This is a convergent plate boundary. From the choices listed, pick the correct d

katen-ka-za [31]

Your answer should be a

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2 years ago

Read 2 more answers

Two circular rods, one steel and the other copper, are joined end to end. Each rod is 0.750 m long and 1.50 cm in diameter. The

Eddi Din [679]

Answer:

(a) Steel rod: $1.1 * 10^{-4}$

Copper rod: $1.88 * 10^{-4}$

(b) Steel rod: $8.3 * 10^{-5} m$

Copper rod: $1.41 * 10^{-4} m$

Explanation:

Length of each rod = 0.75 m

Diameter of each rod = 1.50 cm = 0.015 m

Tensile force exerted = 4000 N

(a) Strain is given as the ratio of change in length to the original length of a body. Mathematically, it is given as

Strain = $\frac{1}{Y} * \frac{F}{A}$

where Y = Young modulus

F = Fore applied

A = Cross sectional area

For the steel rod:

Y = 200 000 000 000 $N/m^{2}$

F = 4000N

A = $\pi r^{2}$ (r = d/2 = 0.015/2 = 0.0075 m)

=> A = $\pi * (0.0075)^{2}$

=> A = 0.000177 $m^{2}$

∴ $Strain = \frac{4000}{200000000000 * 0.000177} \\\\Strain = \frac{4000}{35400000}\\ \\Strain = 0.000113 = 1.13 * 10^{-4}$

For the copper rod:

Y = 120 000 000 000 N/m²

F = 4000N

A = $\pi r^{2}$ (r = d/2 = 0.015/2 = 0.0075 m)

=> A = $\pi * (0.0075)^{2}$

=> A = 0.000177 $m^{2}$

$Strain = \frac{4000}{120 000 000 000 * 0.000177} \\\\Strain = \frac{4000}{21240000}\\ \\Strain = = 1.88 * 10^{-4}$

(b) We can find the elongation by multiplying the Strain by the original length of the rods:

Elongation = Strain * Length

For the steel rod:

Elongation = $1.1 * 10^{-4} * 0.75 = 8.3 * 10^{-5} m$

For the copper rod:

Elongation = $1.88 * 10^{-4} * 0.75 = 1.41 * 10^{-4} m$

6 0

2 years ago

Which of the following statements is/are true? Check all that apply. Check all that apply. Power is the rate at which energy is

AlladinOne [14]

Answer:

True statements:

Power is the rate at which work is done.

Power is the rate at which energy is transformed.

The SI unit of power is watt.

A person is limited in the total work he or she can do by the rate at which energy can be transformed.

Explanation:

The above statements are true.

1. Power is defined as the rate at which work is done.

2. Power is the rate at which energy is transformed. Whenever energy changes its form, or moves from one place to another, the rate at which it makes those changes is described as power.

3. The SI Unit of power is watts. If 1 joule of energy is converted by an object in 1 second then its power is called one watt.

So, the statement<em> 'the SI unit of power is the horsepower' is</em> false.

4. A person is limited in the total work he or she can do by the rate at which energy can be transformed i.e, his power. He is not only limited by the total energy required.

So, the statement <em>'A person is limited in the total work he or she can do only by the total energy required'</em> is not completely true.

5 0

2 years ago

A hammer of mass M is moving at speed v0 when it strikes a nail of negligible mass that is stuck in a wooden block. The hammer i

OleMash [197]

Answer:

i think it would be D

8 0

2 years ago

A bobsledder pushes her sled across horizontal snow to get it going, then jumps in. After she jumps in, the sled gradually slows

Gennadij [26K]

Answer:

d) Gravity, a normal force, and kinetic friction

Explanation:

When the bobsledder pushes her sled across horizontal snow to get it going, after she jumps into the sled there acts a force of gravity on the total mass of the sled including the bobsledder.

The sled moves horizontally and not vertically this means that there is a normal force acting in the vertically upward direction opposite to the gravity.

While the sled moves on the horizontal surface and comes to the rest there acts a kinetic frictional force on the body in the direction opposite to the direction of motion.

3 0

2 years ago