Answer:
a. 0.21 rad/s2
b. 2.205 N
Explanation:
We convert from rpm to rad/s knowing that each revolution has 2π radians and each minute is 60 seconds
200 rpm = 200 * 2π / 60 = 21 rad/s
180 rpm = 180 * 2π / 60 = 18.85 rad/s
r = d/2 = 30cm / 2 = 15 cm = 0.15 m
a)So if the angular speed decreases steadily (at a constant rate) from 21 rad/s to 18.85 rad/s within 10s then the angular acceleration is

b) Assume the grind stone is a solid disk, its moment of inertia is

Where m = 28 kg is the disk mass and R = 0.15 m is the radius of the disk.

So the friction torque is

The friction force is

Since the friction coefficient is 0.2, we can calculate the normal force that is used to press the knife against the stone

Thunder is evidence of electric fields in the atmosphere.
The charge difference between the clouds and earth can be described as parallel conducting plates that produce electric fields in the atmosphere.
could be true
The wind blows because of____.a. Low pressure and high pressure
b. Convection in together atmosphere.
c. Uneven hearing by the sun
*uneven 'hearing' is not a real thing. However there is an uneven 'heating' of the sun
d. All of the above
Answer:
If C is a typo, the answer is D.all of the above.
I did not see the post. But if she actually needs help She can dm me. keep y'all's head up❤