LAB: Thermal Engery Transfer

If there are no unbalanced forces acting on an object, according to Newton's First Law:

Sergio039 [100]

I think its b because when there is unbalanced forces it accelerates.

Hope this helps you out

4 0

2 years ago

When a carpenter shuts off his circular saw, the 10.0 inch diameter blade slows from 4250 rpm to 0.00 in 4.00 s. (a) What is the

MaRussiya [10]

Answer:

(a) $\alpha=-111.26rad/s$

(b) $s=4450.6in$

(c) $8.66in$

Explanation:

First change the units of the velocity, using these equivalents $1rev=2\pi rad$ and $1 min =60s$

$4250rpm(\frac{2\pi rad}{1rev})(\frac{1 min}{60 s} )=445.06rad/s$

The angular acceleration $\alpha$ the time rate of change of the angular speed $\omega$ according to:

$\alpha=\frac{\Delta \omega}{\Delta t}$

$\Delta \omega=\omega_i-\omega_f$

Where $\omega_i$ is the original velocity, in the case the velocity before starting the deceleration, and $\omega_f$ is the final velocity, equal to zero because it has stopped.

$\alpha=\frac{\Delta \omega}{\Delta t} =\frac{\omega_i-\omega_f}{4}\frac{0-445.06}{4} =\frac{-445.06}{4} =-111.26rad/s$

b) To find the distance traveled in radians use the formula:

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

$\theta = 445.06 (4) + \frac{1}{2}(-111.26) (4)^2=1780.24-890.12=890.12rad$

To change this result to inches, solve the angular displacement $\theta$ for the distance traveled $s$ ( $r$ is the radius).

$\theta=\frac{s}{r} \\s=\theta r$

$s=890.12(5)=4450.6in$

c) The displacement is the difference between the original position and the final. But in every complete rotation of the rim, the point returns to its original position. so is needed to know how many rotations did the point in the 890.16 rad of distant traveled:

$\frac{890.12}{2\pi}=141.6667$

The real difference is in the 0.6667 (or 2/3) of the rotation. To find the distance between these positions imagine a triangle formed with the center of the blade (point C), the initial position (point A) and the final position (point B). The angle $\gamma=\frac{2\pi}{3}=\frac{360^o}{3}=120$ is between the two sides known. Using the theorem of the cosine we can find the missing side of the the triangle(which is also the net displacement):

$c^2=a^2+b^2-2abcos(\gamma)$

$c^2=5^2+5^2-2(5)(5)cos(\frac{2\pi}{3} )\\c^2=25+25+25\\c^2=75\\c=5\sqrt{3}=8.66in$

4 0

3 years ago

Which astronomer supported the belief that earth was at the center fo the universe?

MissTica

B. Ptolemy believed that the earth was the center of the universe

4 0

3 years ago

Read 2 more answers

What is biasing and doping

Flura [38]

Answer:

Biasing - Biasing means being unfair to someone or something, and liking the other one or helping them.

Doping - Doping is where a person use drug to get better at sporting and get stronger muscles, such as getting stronger, getting faster and so on. It is mostly used by athletics.

5 0

2 years ago

Read 2 more answers

Squids propel themselves by expelling water. They do this by keeping water in a cavity and then suddenly contracting the cavity

Musya8 [376]

Answer:

v_squid = - 2,286 m / s

Explanation:

This exercise can be solved using conservation of the moment, the system is made up of the squid plus the water inside, therefore the force to expel the water is an internal force and the moment is conserved.

Initial moment. Before expelling the water

p₀ = 0

the squid is at rest

Final moment. After expelling the water

$p_{f}$ = M V_squid + m v_water

p₀ = p_{f}

0 = M V_squid + m v_water

c_squid = -m v_water / M

The mass of the squid without water is

M = 9 -2 = 7 kg

let's calculate

v_squid = 2 8/7

v_squid = - 2,286 m / s

The negative sign indicates that the squid is moving in the opposite direction of the water

8 0

3 years ago