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amm1812
3 years ago
6

A Dodge Stealth is driving at 70 mph on a highway. It passes a BMW going the same direction. The BMW is moving 7 mph backward re

lative the Dodge. What is the velocity of the BMW? Let the positive direction be forward.
a. 63 mph


b. 77 mph


c. −63 mph


d. −77 mph
Physics
1 answer:
Tasya [4]3 years ago
5 0

A Dodge Stealth is driving at 70 mph on a highway. It passes a BMW going the same direction. The BMW is moving 7 mph backward relative the Dodge. 63 mph is the velocity of the BMW

Answer: Option A

<u>Explanation:</u>

Given is the speed of the dodge stealth as 70 mph passing by the BMW moving with 7 mph relative to Dodge. Thereby, to calculate the velocity of BMW, relative velocity concept has to be employed.  

As we know that the relative velocity tells us about relative velocity of mobile reference system as the difference or sum of the initial reference system.

Therefore,

velocity of the BMW =  v_{b}

Velocity of the dodge = v_{d}

Velocity of the BMW with respect to dodge = V_{b d}

As per the formula,

                     v_{b d}=v_{b}-v_{d}

        v_{b} = v_{d} + v_{b d} = 70 + (-7) = 70 - 7 = 63 \mathrm{mph}

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tankabanditka [31]

Answer:

The magnetic field strength inside the solenoid is 5.026\times10^{-3}\ T.

Explanation:

Given that,

Radius = 2.0 mm

Length = 5.0 cm

Current = 2.0 A

Number of turns = 100

(a). We need to calculate the magnetic field strength inside the solenoid

Using formula of the magnetic field strength

Using Ampere's Law

B=\dfrac{\mu_{0}NI}{l}

Where, N = Number of turns

I = current

l = length

Put the value into the formula

B=\dfrac{4\pi\times10^{-7}\times100\times2.0}{5.0\times10^{-2}}

B=0.005026=5.026\times10^{-3}\ T

(b). We draw the diagram

Hence, The magnetic field strength inside the solenoid is 5.026\times10^{-3}\ T.

4 0
3 years ago
The coefficient of linear expansion of ordinary glass is three times that of Pyrex glass. An ordinary glass rod and a Pyrex glas
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Answer:

b. 3 times

Explanation:

Lets take

Coefficient for ordinary glass = α₁

Coefficient for pyrex glass = α₂

 Given that α₁ = 3 α₂

Initial length of both glasses are equal = L

Change in the temperature is also same .= ΔT

We know that change in the length  given as

ΔL =  L α ΔT

Therefore

\dfrac{\Delta L_1}{\Delta L_2}=\dfrac{L\alpha_1\Delta T}{L\alpha_2\Delta T}

\dfrac{\Delta L_1}{\Delta L_2}=\dfrac{3\alpha_2}{\alpha_2}

ΔL₁ = 3ΔL₂

Therefore change in the length of original glass is three time of pyrex glass.

b. 3 times

6 0
3 years ago
Analyze the effects on a passenger riding in a car traveling at
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Without:

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With safety:

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3 years ago
As a box slides down a ramp, friction does 23.0 joules of work. At the bottom of the ramp, the box has 3.8 joules of kinetic ene
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Answer:

The high of the ramp is 2.81[m]

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This is a problem where it applies energy conservation, that is part of the potential energy as it descends the block is transformed into kinetic energy.

If the bottom of the ramp is taken as a potential energy reference point, this point will have a potential energy value equal to zero.

We can find the mass of the box using the kinetic energy and the speed of the box at the bottom of the ramp.

E_{k}=0.5*m*v^{2}\\\\where:\\E_{k}=3.8[J]\\v = 2.8[m/s]\\m=\frac{E_{k}}{0.5*v^{2} } \\m=\frac{3.8}{0.5*2.8^{2} } \\m=0.969[kg]

Now applying the energy conservation theorem which tells us that the initial kinetic energy plus the work done and the potential energy is equal to the final kinetic energy of the body, we propose the following equation.

E_{p}+W_{f}=E_{k}\\where:\\E_{p}= potential energy [J]\\W_{f}=23[J]\\E_{k}=3.8[J]\\

And therefore

m*g*h + W_{f}=3.8\\ 0.969*9.81*h - 23= 3.8\\h = \frac{23+3.8}{0.969*9.81}\\ h = 2.81[m]

8 0
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