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mihalych1998 [28]
3 years ago
9

Un auto de 1000 kg que lleva una velocidad de 72 km/h se detiene en una distancia de 100 metros cuando se le aplican los frenos.

(a) ¿Cuál es la fuerza constante producida por los fre. Nos? (b) Con esta fuerza, ¿cuál seria la distancia de frena do si la velocidad hubiera sido de 36 km/h?
Physics
1 answer:
Flura [38]3 years ago
6 0

Answer:

a)    F = 2000 N , B)   x = 25 m

Explanation:

a) To solve this exercise we can use the relationship between work and kinetic energy

          W = ΔK

The job is

           W = -F x

the negative sign is because the force of the brakes is contrary to the movement

as the car stops its final kinetic energy is zero

           K = ½ m v²

let's substitute

         - F x = 0 - ½ m v²

            F = ½ m v² / x

Let's reduce the magnitudes to the SI system

           v = 72 km / h (1000m / 1km) (1 h / 3600 s) = 20 m / s

let's calculate

          F = ½ 1000 20²/100

          F = 2000 N

b) x = ½ mv2 / F

let's slow down to the SI system

         v = 36 km / h = 10 m / s

let's calculate

             x = ½ 1000 10²/2000

             x = 25 m

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Afina-wow [57]
Acceleration = force / mass = 20 / 2 = 10 m/s^2
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3 years ago
Help with either I don’t understand this I know W=f*d but don’t get how it applies here
rosijanka [135]

Answer:

5) Displacement = +3.125 m

Displacement is in the same direction as the force vector.

6) Force = -53.89 N

Force is in an opposite direction relative to the displacement.

Explanation:

5) We are given;

Force; F = 160 N.

Workdone; W = +500 J

Now, formula for workdone is;

W = Force × displacement

Thus, displacement = Work/force

Displacement = 500/160

Displacement = +3.125 m

Thus, displacement is in the same direction as the force vector.

6) We are given;

Displacement; d = 18 m.

Workdone; W = -970 J

Like in the first answer above,

Workdone = Force × Displacement

Thus;

Force = Workdone/Displacement

Force = -970/18

Force = -53.89 N

Since force is negative and displacement is positive, it means force is in an opposite direction relative to the displacement.

3 0
3 years ago
A car traveling at 27.4 m/s hits a bridge abutment. A passenger in the car, who has a mass of 65.0 kg, moves forward a distance
Minchanka [31]

Answer:

F=43570.9N

Explanation:

We can calculate the acceleration experimented by the passenger using the formula v_f^2=v_i^2+2ad, taking the initial direction of movement as the positive direction and considering it comes to a rest:

a=\frac{v_f^2-v_i^2}{2d}=\frac{-v_i^2}{2d}

Then we use Newton's 2nd Law to calculate the force the passenger of mass m experimented to have this acceleration:

F=ma=\frac{-mv_i^2}{2d}

Which for our values is:

F=\frac{-(65kg)(27.4m/s)^2}{2(0.56m)}=43570.9N

6 0
4 years ago
Which element could provide one atom to make an ionic bond with nitrogen?​
aev [14]

Answer:

boron

aluminum

gallium

indium

thallium

Explanation:

Any of these could work. Nitrogen has 5 valence electrons so you just needed to pick an element that has 3 valence electrons that nitrogen could borrow. This periodic table shows valence electron counts:

8 0
3 years ago
A thin aluminum rod lies along the x-axis and has current of I = 16.0 A running through it in the +x-direction. The rod is in th
coldgirl [10]

Answer:

a) The magnitude of the magnetic field = 7.1 mT

b) The direction of the magnetic field is the +z direction.

Explanation:

The force, F on a current carrying wire of current I, and length, L, that passes through a magnetic field B at an angle θ to the flow of current is given by

F = (B)(I)(L) sin θ

F/L = (B)(I) sin θ

For this question,

(F/L) = 0.113 N/m

B = ?

I = 16.0 A

θ = 90°

0.113 = B × 16 × sin 90°

B = 0.113/16 = 0.0071 T = 7.1 mT

b) The direction of the magnetic field will be found using the right hand rule.

The right hand rule uses the first three fingers on the right hand (the thumb, the pointing finger and the middle finger) and it predicts correctly that for current carrying wires, the thumb is in the direction the wire is pushed (direction of the force; -y direction), the pointing finger is in the direction the current is flowing (+x direction), and the middle finger is in the direction of the magnetic field (hence, +z direction).

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