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3 years ago

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Physics

1 answer:

Alina [70]3 years ago

6 0

Answer:

Find the velocity of a projectile at the highest point, if it is projected with a speed 15ms-1 in the direction 45∘ above horizontla. (take g = 10ms-2) Answer : 15√2ms-1 along horizontal

Explanation:

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A flywheel turns through 26 rev as it slows from an angular speed of 2.9 rad/s to a stop. (a) Assuming a constant angular accele

Misha Larkins [42]

a) The wheel takes 112.7 s to comes to rest

b) The angular acceleration of the wheel is $-0.0257 rad/s^2$

c) The wheel takes 33.0 s to complete 13 revolutions

Explanation:

The rotational motion of the wheel is at constant angular acceleration, so we can use the equivalent of the suvat equations for rotational motion. In particular, to find the time the wheel takes to come to a stop, we use the following:

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

where:

$\theta$ is the angular displacement

$\omega_i$ is the initial angular speed

$\omega_f$ is the final angular speed

t is the time

For the wheel in this problem:

$\omega_i = 2.9 rad/s$

$\omega_f = 0$

$\theta = 26 rev \cdot (2\pi)= 163.4 rad$

And solving for t, we find the time:

$t=\frac{2\theta}{\omega_i + \omega_f}=\frac{2(163.4)}{0+2.9}=112.7 s$

We can find the angular acceleration by using the equation:

$\alpha = \frac{\omega_f - \omega_i}{t}$

where here we have:

$\omega_f = 0$ is the final angular speed

$\omega_i = 2.9 rad/s$ is the initial angular speed

t = 112.7 s is the time

And substituting,

$\alpha = \frac{0-2.9}{112.7}=-0.0257 rad/s^2$

And the negative sign is because the wheel is decelerating.

In order to find the time taken to complete 13 revolutions, we use the following suvat equation:

$\theta=\omega_i t+ \frac{1}{2}\alpha t^2$

where:

$\omega_i = 2.9 rad/s$ is the initial angular speed

$\theta = 13 rev \cdot (2\pi)=81.7 rad$ is the angular displacement

$\alpha=-0.0257 rad/s^2$ is the angular acceleration

Substituting into the equation:

$81.7 = 2.9 t +\frac{1}{2}(-0.0257)t^2\\0.0129t^2-2.9t+81.7 = 0$

which has two solutions:

t = 33.0 s

t = 191.8 s

And here we have to take the first solution (33.0 s), because it corresponds to the first time at which the angular displacement of the wheel is equal to 13 revolutions (the second solution is the time at which the angular displacement of the wheel returns to 13 revolutions, after the wheel has came to rest and it started to rotate in the opposite direction).

Learn more about rotational motions:

brainly.com/question/9575487

brainly.com/question/9329700

#LearnwithBrainly

5 0

4 years ago

What are some factors that might stop a population's exponential growth

lyudmila [28]

So first of all, you might run out of food, which means that there wont be enough to sustain too many animals/people.
Or, you could simply run out of the space to have any more offspring.
One final one is the introduction of a new predator, which would eat the population, making the growth unpredictable.

Hope this helped!!!! :D

3 0

3 years ago

Read 2 more answers

Direct current, DC, flows in a _________ direction while alternating current, AC, the direction of flow ___________. A) single,

kramer

The flow of Direct current (DC) is constant and flows in one direction. Most digital electronics make use of DC. Alternating current (AC) periodically flows in reverse and is mostly used to deliver power to houses, buildings and the like. With that alone, you can already rule out A, C and D.

The answer would then be B. constant, periodically reversing.

4 0

4 years ago

Read 2 more answers

Describe the forest ecosystem with examples

Andreyy89

A forest ecosystem describes the community of plants, animals, microbes and all other organisms in interaction with the chemical and physical features of their environment: Specifically, a terrestrial environment dominated by trees growing in a closed canopy — a forest, in other words.

Hope this helps you buddy! :)

6 0

3 years ago

Read 2 more answers

Ned the skydiver weighs 600 N and is falling at terminal speed. That is, he has sped up until air resistance has built up so muc

natali 33 [55]

Answer:

The work done is 120000 J.

Explanation:

Given that,

Weight = 600 N

Distance = 200 m