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3 years ago

The Atomic number tells us the number of ____ in an atom.

Physics

2 answers:

nadezda [96]3 years ago

6 0

Answer: protons

Explanation:

yawa3891 [41]3 years ago

5 0

Answer:

Protons

Explanation:

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A soccer ball with a mass of 0.45 kg is kicked and is moving at 8.9 m/s. Find the kinetic

strojnjashka [21]

Answer:

17.82J

Explanation:

Kinetic energy = 1/2 mv^2

Given

Mass M = 0.45kg

Velocity v = 8.9m/s

Therefore,

K.E. = 1/2 x 0.45 x (8.9)^2

= 1/2 x 0.45 x (8.9 x 8.9)

= 1/2 x 0.45 x 79.21

Multiply through

= 35.6445/2

= 17.82J

The kinetic energy of the ball is 17.82J

3 0

3 years ago

boris the bear is lumbering along at a constant rate of 4.0 m/s. if he walks for 600.0 seconds, how far will he travel?

irina1246 [14]

Answer: 2400m

Explanation: 2400m because 600 times 4 equals 2400

6 0

3 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) $s=4450.6in$

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):