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3 years ago

About when was the sail developed, making travel possible on the open water?

Physics

1 answer:

dalvyx [7]3 years ago

4 0

The first sail was developed in 1300 BC in Mesopotamia

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At take off, a plane flies 100 km north before turning to fly 200 km east. How far is its destination from where the plane took

Snowcat [4.5K]

The answer is 300 km

To the destination

4 0

3 years ago

A merry-go-round with a rotational inertia of 600 kg m2 and a radius of 3. 0 m is initially at rest. A 20 kg boy approaches the

Margaret [11]

Hi there!

$\boxed{\omega = 0.38 rad/sec}$

We can use the conservation of angular momentum to solve.

$\large\boxed{L_i = L_f}$

Recall the equation for angular momentum:

$L = I\omega$

We can begin by writing out the scenario as a conservation of angular momentum:

$I_m\omega_m + I_b\omega_b = \omega_f(I_m + I_b)$

$I_m$ = moment of inertia of the merry-go-round (kgm²)

$\omega_m$ = angular velocity of merry go round (rad/sec)

$\omega_f$ = final angular velocity of COMBINED objects (rad/sec)

$I_b$ = moment of inertia of boy (kgm²)

$\omega_b$ = angular velocity of the boy (rad/sec)

The only value not explicitly given is the moment of inertia of the boy.

Since he stands along the edge of the merry go round:

$I = MR^2$

We are given that he jumps on the merry-go-round at a speed of 5 m/s. Use the following relation:

$\omega = \frac{v}{r}$

$L_b = MR^2(\frac{v}{R}) = MRv$

Plug in the given values:

$L_b = (20)(3)(5) = 300 kgm^2/s$

Now, we must solve for the boy's moment of inertia:

$I = MR^2\\I = 20(3^2) = 180 kgm^2$

Use the above equation for conservation of momentum:

$600(0) + 300 = \omega_f(180 + 600)\\\\300 = 780\omega_f\\\\\omega = \boxed{0.38 rad/sec}$

8 0

2 years ago

Bones provide both structure and protection for the body. A t. B f

vovikov84 [41]

Answer:

what are you saying man. They do provide structure.

Explanation:

6 0

3 years ago

Which measure of an earthquake depends on how close you are to the focus?

Vsevolod [243]

<span>The intensity of an earthquake is dependent on one's proximity to the focus of the quake, also called the "epicenter" and is based on observations of the shaking of the ground on humans, structures, and the natural landscape.</span>

8 0

3 years ago

An 80-kilogram skier slides on waxed skis along a horizontal surface of snow at constant velocity while pushing with his poles.

ivann1987 [24]

Answer:

The force F is created by the reaction of the Earth to the thrust of the rods, whereby the thrust is created by a force of action and reaction.

Explanation:

To answer this question, let's write Newton's second law of the two axes

Y Axis

Fy + N - W = 0

Fy + N = W

X axis

Fx - fr = 0

Fx = fr

The force F is created by the reaction of the Earth to the thrust of the rods, whereby the thrust is created by a force of action and reaction.

The direction of this force is along the length of the rods that are in an Angle, where the x and y components of the force come from

In general this force is small because the rubbing of the skis is small

8 0

3 years ago