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Alex
3 years ago
5

a motorcar is moving with a velocity of 108 km / h and it takes 4s to stop after the brakes are applied calculate the force exer

ted by the brakes on the motorcar if it's mass along with the passengers is 1000 kg​
Physics
2 answers:
vladimir1956 [14]3 years ago
7 0

Answer:

-7500 N

Explanation:

v₀ = 108 km/h = 30 m/s

v = 0 m/s

t = 4 s

a = Δv / Δt

a = (0 m/s − 30 m/s) / 4 s

a = -7.5 m/s²

F = ma

F = (1000 kg) (-7.5 m/s²)

F = -7500 N

NikAS [45]3 years ago
3 0

Answer:-7500

Explanation v₀ = 108 km/h = 30 m/s

v = 0 m/s

t = 4 s

a = Δv / Δt

a = (0 m/s − 30 m/s) / 4 s

a = -7.5 m/s²

F = ma

F = (1000 kg) (-7.5 m/s²)

F = -7500 N

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Complete question is;

A single-phase 60-Hz overhead power line is symmetrically supported on a horizontal cross arm. Spacing between the centers of the conductors acing between the centers of the conductors (say, a and b) is 2.5 m. A telephone line is also symmetrically supported on a horizontal cross arm 1.8 m directly below the power line. Spacing between the centers of these conductors (say, c and d) is 1.0 m.

The mutual inductance per unit length between circuit a-b and circuit c-d is given as 4 x 10^(-7) ln √((D_ad × D_bc)/(D_ac × D_bd)) H/m

where, for example, D_ad denotes the distance in meters between conductors a and d.

a. Hence, compute the mutual inductance per kilometer between the power line and the telephone line.

b. Find the 60-Hz voltage per kilometer induced in the telephone line when the power line carries 150 A

Answer:

A) M = 1.01 × 10^(-4) H/km

B) v_cd = 5.712 V/km

Explanation:

A) From the distances given in the question, we can deduce that;

D_ac = √(((2.5/2) - (1/2))² + 1.8²)

D_ac = 1.95 m

Also;

D_ad = √(((2.5/2) + (1/2))² + 1.8²)

D_ad = 2.51 m

I_a and I_b are put of phase by 180°. Thus, due to a and b, the flux linkages to c and d is given as;

φ_cd = 4 x 10^(-7)I_a( ln (2.51/1.95))

Mutual inductance per km is given as;

M = φ_cd/I_a

Thus;

M = 4 x 10^(-7)( ln (2.51/1.95))

M = 1.01 × 10^(-7) H/m

Per km;

M = 1.01 × 10^(-7) × 1000

M = 1.01 × 10^(-4) H/km

B) voltage per km is gotten by;

v_cd = ωMI

Now, ω = 2πf = 2π × 60 = 377 rad/s

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v_cd = 5.712 V/km

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3 years ago
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Setler79 [48]

Given Information:  

Voltage of circuit A = Va = 208 Volts

Current of circuit A = Ia = 40 Amps

Voltage of circuit B = Vb = 120 Volts

Current of circuit B = Ib = 20 Amps

Required Information:  

Ratio of power = Pa/Pb = ?

Answer:  

Ratio of power = Pa/Pb = 52/15

Explanation:  

Power can be calculated using Ohm's law

P = VI

Where V is the voltage and I is the current flowing in the circuit.

The power delivered by circuit A is

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The power delivered by circuit B is

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7 0
3 years ago
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