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1 month ago
6

f a car is speeding down a road at 40 miles/hour (mph), how long is the stopping distance D40 compared to the stopping distance

D25 if the driver were going at the posted speed limit of 25 mph? Express your answer as a multiple of the stopping distance at 25 mph. Note that D25 is already written for you, so just enter the number. View Available Hint(s)
Physics
1 answer:
kicyunya [3.2K]1 month ago
5 0

Answer:

D40 = 2.56 × D25

This means the stopping distance at 40 mph is 2.56 times that at 25 mph

Explanation:

provided data

speed = 40 miles/hour

distance = D40

speed limit = 25 miles/hour

distance = D25

to determine

express how the stopping distance relates to the 25 mph distance

solution

it is established that stopping distance varies directly with the square of the speed

thus speed ratio is

initial speed = \frac{40}{25}

thereby, initial speed = 1.6

so

stopping distance increase = (1.6)²

\frac{D40}{D25} = (1.6)²

\frac{D40}{D25} = 2.56

therefore

D40 = 2.56 × D25

This shows that the stopping distance at 40 mph is 2.56 times that at 25 mph

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An 800-N billboard worker stands on a 4.0-m scaffold weighing 500 N and supported by vertical ropes at each end. How far would t
Maru [3345]

Answer:

2.5 m

Explanation:

Billboard worker's weight = 800 N

Number of ropes = 2

Length of scaffold = 4 m

Weight of scaffold = 500 N

Tension present in rope = 550 N

The total torques will be

-800(4-x)-500\times 2+550\times 4=0\\\Rightarrow -800(4-x)=500\times 2-550\times 4\\\Rightarrow -800(4-x)=-1200\\\Rightarrow -x=\dfrac{1200}{800}-4\\\Rightarrow -x=-2.5\\\Rightarrow x=2.5\ m

The worker is positioned at 2.5 m

7 0
1 month ago
Because of your knowledge of physics, you have been hired as a consultant for a new James Bond movie, "Oldfinger". In one scene,
Softa [3030]

Answer:

v = [√(g/2h)]L

Explanation:

Let v represent the initial horizontal speed, and t denote the duration James Bond takes to leap off the ledge of length, L.

Thus, we derive vt = L, which leads to t = L/v

Additionally, considering that Bond begins with no horizontal velocity, he descends freely over the height, h; thus the equation y - y' = ut - 1/2gt² is applicable, where y = 0 (top of the cliff) and y' = -h, u = 0 (initial vertical speed), g = acceleration due to gravity = 9.8 m/s², and t = the time required to leap from the cliff = L/v.

By substituting these parameters into the equation, we obtain

y' - y = ut - 1/2gt²

-h - 0 = 0 × t - 1/2g(L/v)²

-h  = - 1/2gL²/v²

v² = gL²/2h

taking the square root of both sides gives us

v = [√(g/2h)]L

Therefore, James Bond's required minimum horizontal velocity is v = [√(g/2h)]L

8 0
20 days ago
In a fluorescent tube of diameter 3 cm, 3 1018 electrons and 0.75 1018 positive ions (with a charge of e) flow through a cross-s
Softa [3030]

Answer:

The current flowing through the tube is 0.601 A

Explanation:

Given data;

the diameter of the fluorescent tube is d = 3 cm

the incoming negative charge in the tube is -e = 3 x 10¹⁸ electrons/second

the outgoing positive charge equals +e = 0.75 x 10¹⁸ electrons/ second

The current within the fluorescent tube results from both positive and negative charges which contribute to maintaining electrical neutrality in the conductor (fluorescent tube).

Q = It

I = Q/t

where;

I signifies current in Amperes (A)

Q represents charge measured in Coulombs (C)

t denotes time which is in seconds (s)

1 electron (e) accounts for 1.602 x 10⁻¹⁹ C

Thus, 3 x 10¹⁸ e/s can be computed as

= (3 x 10¹⁸ e/s  x 1.602 x 10⁻¹⁹ C) / 1e

= 0.4806 C/s

This reflects the negative charge per second (Q/t) = 0.4806 C/s

Meanwhile, the positive charge per second amounts to

(0.75 x 10¹⁸ e/s  x 1.602 x 10⁻¹⁹ C) / 1e

Thus, the positive charge per second is equal to 0.12015 C/s

The total charge per second in the tube is then obtained by summing both charges: Q / t = (0.4806 C/s + 0.12015 C/s)

                                                                I = 0.601 A

Therefore, the current within the tube computes to 0.601 A

7 0
27 days ago
A firecracker breaks up into several pieces, one of which has a mass of 200 g and flies off along the x-axis with a speed of 82.
Maru [3345]

Answer:

La magnitud del momento total es de 21.2 kg m/s y su dirección es de 39.5° respecto al eje x.

Explanation:

¡Hola!

El momento total se calcula como la suma de los momentos de las piezas.

El momento de cada pieza se calcula de la siguiente manera:

p = m · v

Donde:

p = momento.

m = masa.

v = velocidad.

El momento es un vector. La pieza de 200 g se mueve a lo largo del eje x, por lo que su momento será:

p = (m · v, 0)

p = (0.200 kg · 82.0 m/s, 0)

p = (16.4 kg m/s, 0)

La pieza de 300 g se mueve a lo largo del eje y. Su vector momento será:

p =(0, m · v)

p = (0, 0.300 kg · 45.0 m/s)

p = (0, 13.5 kg m/s)

El momento total es la suma de cada momento:

Momento total = (16.4 kg m/s, 0) + (0, 13.5 kg m/s)

Momento total = (16.4 kg m/s + 0, 0 + 13.5 kg m/s)

Momento total = (16.4 kg m/s, 13.5 kg m/s)

La magnitud del momento total se calcula de la siguiente manera:

|p| = \sqrt{(16.4 kgm/s)^2+(13.5 kg m/s)^2}= 21.2 kg m/s

La dirección del vector de momento se calcula utilizando trigonometría:

cos θ = px/p

Donde px es el componente horizontal del momento total y p es la magnitud del momento total.

cos θ = 16.4 kg m/s / 21.2 kg m/s

θ = 39.3 (39.5° si no redondeamos la magnitud del momento total)

<pFinalmente, la magnitud del momento total es 21.2 kg m/s y su dirección es 39.5° respecto al eje x.

6 0
1 month ago
What is the magnitude of the relative angle φ
kicyunya [3294]

The complete question is;

A ski jumper descends a ramp and exits the ski track at a horizontal speed of 24 m/s. The slope at the landing site angles downwards at θ = 59◦. The acceleration due to gravity is 9.8 m/s².

What is the value of the relative angle φ at which the ski jumper makes contact with the slope? Provide the answer in degrees.

Answer:

14.08°

Explanation:

The time taken can be calculated using the formula;

t = (2V_x•tan θ)/g

t = (2 × 24 × tan 59)/9.8

t = 8.152 s

Next, the slope of the trajectory at the impact point is determined by;

tan α = V_y/V_x

Given V_x = 24 m/s

We will find V_y using;

v = gt

Therefore;

V_y = gt

V_y = 9.8 × (8.152) = 78.89 m/s

Thus;

tan α = 78.89/24

tan α = 3.2871

α = tan^(-1) 3.2871

α = 73.08°

Consequently;

Relative angle φ = α - θ = 73.08 - 59 = 14.08°

6 0
1 month ago
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