Aspinning wheel on a fireworks display is initially rotating in a counterclockwise direction. the wheel has an angular acceleration of -7.80 rad/s2. because of this acceleration, the angular velocity of the wheel changes from its initial value to a final value of -22.4 rad/s. while this change occurs, the angular displacement of the wheel is zero. (note the similarity to that of a ball being thrown vertically upward, coming to a momentary halt, and then falling downward to its initial position.) find the time required for the change in the angular velocity to occur.

5.74s

Explanation:

We can first solve for the initial angular velocity using the following formula

Where is the final angular velocity, is the angular acceleration and is the angular displacement

So for the wheel to get from 22.4 to -22.4 with angular acceleration of -7.8 then the time it takes must be

when a device is used in a circuit in which the voltage is 81 v, the current flowing through the device is 3 a. what is the resistance of the device?

a. 27 ω

b. 40.5 a

c. 243 ω

d. 243 a

the correct answer is a. 27

answer: the metamorphic rocks are formed when they are exposed to high pressure and high temperatures. this happens when one of the earth's plates comes in contact with the other plate by traveling in opposite directions, straight into each other or slipping under one another. the friction that is caused by this activity results in   melting of rocks and when it cools they are known as metamorphic rocks. this process needs a controlled amount of pressure and temperature otherwise it may turn into magma.