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
Answer:
Professor Hawking had just turned 21 when he was diagnosed with a very rare slow-progressing form of ALS, a form of motor neurone disease (MND). He was at the end of his time at Oxford when he started to notice early signs of his disease. He was getting more clumsy and fell over several times without knowing why.
Explanation:
none
And what about it?????????
Answer:
The inertial force of the body
Explanation:
Everybody that is moving in a curved path has an inertial force called centrifugal force.
The counterforce of the centrifugal force is called the centripetal force. It also acts on every rotating body.
This force is always directed towards the center of the origin of the curve.
The velocity of the object changes its direction and magnitude at any instant of time. But the speed and angular velocity of the object remains the same for uniform circular motion.
So, according to the Newtonian mechanics, it is the inertial force of the body responsible for the centripetal force.
