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

Please answer this question
Answer:he formula for average speed is (total distance/total time)
the y-component does not matter in this problem. so do 6.26(cos45)=4.43m/s to find the x-component velocity which is constant throughout the duration of the flight. the total distance is 2L because he travels distance L twice.
the total time is ((time in water)+(time out of water)) since you dont have time you must eliminate it. to do this you need (distance)/(time)=velocity
solve for time and you get T=D/V
time in water is L/3.52 and time out of water is L/4.43
add them together and you get (4.43L+3.52L)/(15.59) = 7.95L/15.59
that value is your total time
divide you total distance (2L) by total time (7.95L/15.59) and the Ls cancel out and you get
(31.18)/(7.95) = 3.92 m/s = Average Speed
Explanation:
The elements which have similar behavior are Barium, strontium and beryllium.
Explanation: