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3 years ago

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A bicyclist in the Tour de France crests a mountain pass as he moves at 15 km/h. At the bottom, 4.2 km farther, his speed is 65

km/h. Estimate his average acceleration while riding down the mountain.

1 answer:

OLga [1]3 years ago

6 0

18 km/hr*1000m/km*1 hr/3600 sec= 5 m/sec

<span>85 km/hr= 23.6 m/s </span>

<span>distance = 4000m </span>

<span>distance= initial distance+initial velocity*time+ 1/2 acceleration*time^2 </span>

<span>initial distance=0 </span>

<span>4000= 5.0*t+ 1/2 (accel)(time)^2 </span>

<span>Velocity=initial velocity+ acceleration * time </span>

<span>23.6 m/s= 5.0 m/s+ acceleration * time </span>

<span>We now have two equations and two unknowns. Solve them and you have your answer.</span>

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A body is moving with an acceleration of 60 m/s^2(square).If the force applied to the body is 4200N.Calculate its mass.

Pavel [41]

Hello, for this use the <u>2nd law of Newton:</u>

F = ma

Replacing:

4200 N = m * 60 m/s^2

Resolving:

4200 N / 60 m/s^2 = m

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Answer:

Explanation:

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3 years ago

A student decides to give his bicycle a tune up. He flips it upside down (so there's no friction with the ground) and applies a

aleksklad [387]

Answer:

$V=9.2565m/s$

Explanation:

From the question we are told that:

Force $F = 34 N$

Time $t = 0.6 s$

Length of pedal $l_p=16.5cm \approx0.165m$

Radius of wheel $r = 33 cm = 0.33 m$

Moment of inertia, $I = 1200 kgcm2 = 0.12 kg.m2$

Generally the equation for Torque on pedal $\mu$ is mathematically given by

$\mu=F*L\\\mu=34*0.165$

$\mu=5.61N.m$

Generally the equation for angular acceleration $\alpha$ is mathematically given by

$\alpha=\frac{\mu}{l}$

$\alpha=\frac{5.61}{0.12}$

$\alpha=46.75$

Therefore Angular speed is \omega

$\omega=\alpha*t$

$\omega=(46.75)*(0.6)$

$\omega=28.05rad/s$

Generally the equation for Tangential velocity V is mathematically given by

$V=r\omega$

$V=(0.33)(28.05)$

$V=9.2565m/s$

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3 years ago

A light ray traveling through medium 1, index of refraction n1n1n_1 = 1.75, reaches the interface between medium 1 and medium 2,

horrorfan [7]

Answer:

θ₁ = 35.32°

Explanation:

given,

refractive index of medium 1 = n₁ = 1.75

refractive index of medium 2 = n₂ = 1.24

condition to describe the refracted angle

$\theta_{refracted} + \theta_{reflected}=90^0$

$\theta_2 = 90^0-\theta_1$ ...(1)

Using Snell's Law

n₁ sin θ₁ = n₂ sin θ₂

θ₁ , θ₂ is the angle of incidence and refractive index

n₁. n₂ is the refractive index medium 1 and medium 2

1.75 x sin θ₁ = 1.24 x sin θ₂

From equation (1)

1.75 x sin θ₁ = 1.24 x sin (90-θ₁)

1.75 sin θ₁ = 1.24 cos θ₁

tan θ₁ = 0.708

θ₁ = 35.32°

Hence, angle of incidence is equal to θ₁ = 35.32°

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3 years ago