A)We know the formula of the angular speed is ω = 2π / TWhere T is the time period.When second hand completes one revolution then the time taken is 60s.So T = 60sThen the angular speed of the second hand is ω= 2π / (60s) = 0.1047 rad/sb)When the minute hand completes one revolution the time taken is T = 1 hr = 3600sThen the angular speed of the minute hand is ω =(2π) / (3600s) = 0.001745 rad/sc)When the hour hand completes one revolution then the timeperiod is T = 12hrs = (12)(3600)sThen the angular speed of the hour hand is ω =(2π) / [(12)(3600)s] = 1.45444 x 10^-4 rad/s
Assuming that the can is motionless, we can then assume that the vertical component of T = mg and that Fe = the horizontal component of T.
<span> Since T itself is larger than it's vertical or horizontal components separately, then T is greater than all the forces.</span>
Car is moving on the glassy slope with constant speed
Now we know that
so acceleration is rate of change in velocity
as we know that velocity is constant here so acceleration is zero
so here
now as we know by Newton's II law
since a = 0
so net force will be ZERO on it during this motion
Answer:
- Direct current is a current in which electrons flow in one direction only
- Alternating current is a current in which the direction of the electron flow reverses periodically - so, half a cycle forward, half a cycle backward
There are several advantages of using alternating currents for the transmission of electricity across a country, over large distances. The main advantages are:
- The voltage of alternating currents can be easily increased/decreased by using transformers. For instance, a transformer is used at the beginning of the transmission line to increase the voltage (electricity is transmitted at high voltage in order to reduce dissipated power), and then another transformer is used before the electricity enters the houses, in order to decrease the voltage. Transformers only work with alternating currents.
- It is easy to interrupt the flow of an alternating current, because its value naturally becomes zero every half a cycle, so this is useful in case the current must be interrupted.
