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3 years ago

A car travels in a straight line for 5 h at a constant speed of 72 km/h. What is it’s acceleration

Physics

1 answer:

Luda [366]3 years ago

4 0

Answer:

$a \approx \: 0.001 \: m {s}^{ - 2}$

Explanation:

Given:

$initial \: velocity \: (u) = 0 \\ \\ Final \: Velocity \: (v) = 72 km /h \\ \\ Time \: (t) = 5 \: hours \\ \\ Acceleration \: (a) =? \\ \\ \because \: a = \frac{v - u}{t} \\ \\ \therefore \: a = \frac{72 - 0}{5} \\ \\ a = \frac{72}{5} \\ \\ a = 14.5 \: km {h}^{ - 2} \\ \\ a = \frac{14.5 \times 1000}{3600\times 3600} \: m {s}^{ - 2} \\ \\ a = 0.00111882716 \\ \\ a \approx \: 0.001 \: m {s}^{ - 2}$

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Two loudspeakers are placed on a wall 2 m apart. A listener stands directly in front of one of the speakers, 81.7 m from the wal

OverLord2011 [107]

Answer:

The phase difference is $\Delta \phi = 1.9995 rad$

Explanation:

From the question we are told that

The distance between the loudspeakers is $d = 2m$

The distance of the listener from the wall $D = 81.7 \ m$

The frequency of the loudspeakers is $f = 4450Hz$

The velocity of sound is $v_s = 343 m/s$

The path difference of the sound wave that is getting to the listener is mathematically represented as

$\Delta z =\sqrt{d^2 + D^2} -D$

Substituting values

$\Delta z =\sqrt{2^2 + 81.7^2 } -81.7$

$\Delta z =0.0245m$

The phase difference is mathematically represented as

$\Delta \phi$ = $\frac{2 \pi}{\lambda } * \Delta z$

Where $\lambda$ is the wavelength which is mathematically represented as

$\lambda = \frac{v_s }{f}$

substituting value

$\lambda = \frac{343 }{4450}$

$\lambda = 0.0770 m$

Substituting value into the equation for phase difference

$\Delta \phi$ = $\frac{2 * 3.142 * 0.0245}{0.0770}$

$\Delta \phi = 1.9995 rad$

8 0

4 years ago

One end of a thin rod is attached to a pivot, about which it can rotate without friction. Air resistance is absent. The rod has

Scrat [10]

Answer:

5.24 m/s

Explanation:

So for the rod to be able to rise upward to the straight up position, the kinetic energy caused by linear speed v0 must be just enough to convert into the potential energy.

Since the rod is uniform in mass, we can treat the body as 1 point, at its center of mass, or geometric center, aka 0.35 / 2 = 0.175 m from the pivot.

For the rod to swing from bottom to top, the center must have moved a distance of h = 0.175 * 2 = 0.35 m, vertically speaking.

Since we neglect friction and air resistance, according to the law of energy conservation then:

$E_k = E_p$

$mv^2/2 = mgh$

Where v is the speed at the center of mass, g = 9.81 m/s2 is the gravitational acceleration, and m is the mass. We can divide both sides by m

$v^2 = 2gh = 2*9.81*0.35 = 6.867$

$v = \sqrt{6.867} = 2.62 m/s$

As this is only the speed at the center of mass, the speed at the bottom end would be different, to calculate this, we need to find the common angular speed:

$\omega = v / r = 2.62 / 0.175 = 14.97 rad/s$

Where r is the rotation radius, or the distance from pivot point to the center of mass

$v_0 = \omega R = 14.97*0.35 = 5.24 m/s$

Where R is the distance from the pivot to the bottom end of the rod

5 0

3 years ago

1. ________________electricity is the type of electricity commonly used in homes and businesses throughout the world.

amid [387]

Number 1 is letter A

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JulijaS [17]

Answer:

acceleration

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3 years ago

What evidence supports the conclusion that a chemical reaction has occurred?

GalinKa [24]

Answer:

Precipitation formed

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Explanation:

3 0

2 years ago