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2 years ago

Jin walked 4 km on a straight path to get to the sandwich shop. He traveled 30° south of east.

Physics

2 answers:

Molodets [167]2 years ago

3 0

Answer: -2 km

Explanation:

If we imagine Jin's movement to be the hypothenuse of a right triangle, then the southern component of Jin's movement corresponds to the side of the triangle opposite to the angle of 30 degrees. Therefore, the magnitude of this southern component is given by

However, the angle of 30 degrees is south of east: this means that the direction of this southern component is south, and since we generally take north as positive direction, we must add a negative sign, so the correct answer is

-2 km

DanielleElmas [232]2 years ago

3 0

Answer: The component is 2km

Explanation:

Jim walked 4km on a straight path, and the angle is 30° south of the east (so, looking at the east direction, he walked with 30° angle in direction to the south)

So in the rectangle triangle, the east segment is the adjacent side, and the south segment is the opposite side. And 4km is the length of the hypotenuse.

Here you can remember the rule:

soh-cah-toa

this means Sin(a)=Opposite side/hypotenuse

cos(a) = adjacent side/hypotenuse

tan(a) = opposite side/adjacent side

where a is the angle, in this case, a= 30°

Them if we want to find the southern component, we must do:

S = 4km*sin(30°) = 2km

Them the component in the southern direction is 2km

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1 year ago

An 18-cm-long bicycle crank arm, with a pedal at one end, is attached to a 20-cm-diameter sprocket, the toothed disk around whic

Tpy6a [65]

Answer:

Part a)

$a = 0.056 m/s^2$

Part b)

$L = 7.85 m$

Explanation:

Part a)

Angular speed of the pedal is changing from 60 rpm to 90 rpm in 10 s

so the angular acceleration is given as

$\alpha = \frac{\omega_2 - \omega_1}{\Delta t}$

so we will have

$\alpha = \frac{2\pi(\frac{90}{60}) - 2\pi(\frac{60}{60})}{10}$

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now the tangential acceleration of the pedal is given as

$a = r \alpha$

$a = 0.18 \times 0.314$

$a = 0.056 m/s^2$

Part b)

Total angular displacement made by the sprocket in the interval of 10 s is given as

$\theta = \frac{\omega_f + \omega_i}{2} t$

$\theta = \frac{2\pi (\frac{90}{60}) + 2\pi (\frac{60}{60})}{2}(10)$

$\theta = 78.5 radian$

now length of the chain passing over it is given as

$L = R\theta$

$L = 0.10 \times 78.5$

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2 years ago

Suppose the circumference of a bicycle wheel is 2 meters. If it rotates at 1 revolution per second when you are riding the bicyc

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Answer:

Explanation:

We have given circumference C = 2 meters

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We know that circumference $C=2\pi r$ , where r is the radius of circumference

So $2=2\pi \times r$

r = 0.318 meter

Linear velocity $v=r\omega =0.318\times 2\times \pi =2m/sec$

So option C will be the correct option

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2 years ago

A steel casting weighing 2 kg has an initial temperature of 500°c; 25 kg of water initially at 25°c is contained in a perfectly

SCORPION-xisa [38]

Plan: Use Q = m · c · ΔT three times. Hot casting cools ΔT_hot = 500°C - Tf. Cold water and steel tank heat ΔT_cold = Tf - 25°C. Set Q from hot casting cooling = Q from cold tank heating.
here
m_cast · c_steel · ΔT_hot = (m_tank · c_steel + m_water · c_water) · ΔT_cold

m_cast · c_steel · (500°C - Tf) = (m_tank · c_steel + m_water · c_water) · (Tf - 25°C)

2.5 kg · 0.50 kJ/(kg K°) · (500°C - Tf) = (5 kg· 0.50 kJ/(kg K°) + 40 kg· 4.18 kJ/(kg K°)) · (Tf - 25°C)

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3 0

2 years ago

Read 2 more answers

At some airports there are speed ramps to help passengers get from one place to another. A speed ramp is a moving conveyor belt

Volgvan

Answer:

It takes you 32.27 seconds to travel 121 m using the speed ramp

Explanation:

Lets explain how to solve the problem

- The speed ramp has a length of 121 m and is moving at a speed of

2.2 m/s relative to the ground

- That means the speed of the ramp is 2.2 m/s

- You can cover the same distance in 78 seconds when walking on

the ground

Lets find your speed on the ground

Speed = Distance ÷ Time

The distance is 121 meters

The time is 78 seconds

Your speed on the ground = 121 ÷ 78 = 1.55 m/s

If you walk at the same rate with respect to the speed ramp that

you walk on the ground

That means you walk with speed 1.55 m/s and the ramp moves by

speed 2.2 m/s

So your speed using the ramp = 2.2 + 1.55 = 3.75 m/s

Now we want to find the time you will take to travel 121 meters using

the speed ramp

Time = Distance ÷ speed

Distance = 121 meters

Speed 3.75 m/s

Time = 121 ÷ 3.75 = 32.27 seconds

It takes you 32.27 seconds to travel 121 m using the speed ramp

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2 years ago