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3 years ago

PLEASEEE HELPPPP

Physics

2 answers:

Evgen [1.6K]3 years ago

6 0

Answer:

The average car speed is 25.4 m/s

Explanation:

The definition of average speed is the total distance traveled between the total time

Vm = dx/dt (1)

To be able to use this equation let's calculate the total carriage distance

Xt = X1 + X2

X1 = 10 miles 1609 m / 1 miles = 16090 m

X2 = 10 miles 1609 m / 1miles = 16090 m

XT = 32180 m

Now let's calculate the total time

v = d / t

t = d / v

t1 = x1 / v1

t2 = x2 / v2

t1 = 16090/22

t1 = 731.36 s

t2 = 16090/30

t2 = 536.33 s

t all = t1 + t2

t all = 731.36 +536.33

t all = 1267.69 s

Having these values we use the initial equation

Vm = d / t

Vm = 32180 /1267.69

Vm = 25.38 m / s

The average car speed is 25.4 m/s

solniwko [45]3 years ago

5 0

Answer:

Explanation:

average speed more than 25.0m/s.

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A plane has a mass of 360,000 kg takes-off at a speed of 300 km/hr. i) What should be the minimum acceleration to take off if th

melomori [17]

Answer:

i) the minimum acceleration to take off is 22500 km/h²

ii) the required time needed by the plane from starting to takeoff is 0.0133 hrs

iii) required force that the engine must exert to attain acceleration is 625 kN

Explanation:

Given the data in the question;

mass of plane m = 360,000 kg

take of speed v = 300 km/hr = 83.33 m/s

What should be the minimum acceleration to take off if the length of the runway is 2.00 km

from Newton's equation of motion;

v² = u² + 2as

we know that a plane starts from rest, so; u = 0

given that distance S = 2 km

we substitute

(300)² = 0² + ( 2 × a × 2 )

90000 = 4 × a

a = 90000 / 4

a = 22500 km/h²

Therefore, the minimum acceleration to take off is 22500 km/h²

ii) At this acceleration, how much time would the plane need from starting to takeoff.

from Newton's equation of motion;

v = u + at

we substitute

300 = 0 + 22500 × t

t = 300 / 22500

t = 0.0133 hrs

Therefore, the required time needed by the plane from starting to takeoff is 0.0133 hrs

iii) What force must the engines exert to attain this acceleration

we know that;

F = ma

acceleration a = 22500 km/hr² = 1.736 m/s²

so we substitute

F = 360,000 kg × 1.736 m/s²

F = 624960 N

F = 625 kN

Therefore, required force that the engine must exert to attain acceleration is 625 kN

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3 years ago

Two coils close to each other have a mutual inductance of 32 mH. If the current in one coil decays according to I=I0e−αt, where

fiasKO [112]

The emf induced in the second coil is given by:

V = -M(di/dt)

V = emf, M = mutual indutance, di/dt = change of current in the first coil over time

The current in the first coil is given by:

i = i₀ $e^{-at}$

i₀ = 5.0A, a = 2.0×10³s⁻¹

i = 5.0e^(-2.0×10³t)

Calculate di/dt by differentiating i with respect to t.

di/dt = -1.0×10⁴e^(-2.0×10³t)

Calculate a general formula for V. Givens:

M = 32×10⁻³H, di/dt = -1.0×10⁴e^(-2.0×10³t)

Plug in and solve for V:

V = -32×10⁻³(-1.0×10⁴e^(-2.0×10³t))

V = 320e^(-2.0×10³t)

We want to find the induced emf right after the current starts to decay. Plug in t = 0s:

V = 320e^(-2.0×10³(0))

V = 320e^0

V = 320 volts

We want to find the induced emf at t = 1.0×10⁻³s:

V = 320e^(-2.0×10³(1.0×10⁻³))

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3 years ago

When the frequency of an ac circuit is decreased, the current in the circuit increases. which combination of elements is most li

zaharov [31]

Answer:

The combination of elements most likely to comprise the circuit are resistor, inductor and capacitor

Explanation:

The impedance of an LCR circuit shown as

Z = √R² + (X↓l - X↓c)²

Z = √R² + (2π∨L - 1/2π∨c)²

Variation of Z with respect to υ is shown in the figure.

As υ increases, Z decreases and so the current increases.

At υ = υ↓r

Z is minimum, current is maximum. Beyond

υ = υ↓r

Z increases and so current decreases.

so the combination of circuit elements that is most suitable to comprise

the circuit is R, L and C.

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in a one dimensional collision, a 4kg object and 6 kg onject have initial velocity. calculate the magnitude of impulse

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mass 2 = 6kg

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velocity 2 = 2ms^1

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= 12

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