Answer:
Simple machines are useful because they reduce effort or extend the ability of people to perform tasks beyond their normal capabilities. Simple machines that are widely used include the wheel and axle, pulley, inclined plane, screw, wedge and lever.
Answer:
a ) 2.368 rad/s
b) 3.617 rad/s
Explanation:
the minimum angular velocity that Prof. Stefanovic needs to spin the bucket for the water not to fall out can be determined by applying force equation in a circular path
i.e
------ equation (1)
where;


Also

since; that is the initial minimum angular velocity to keep the water in the bucket
Now; we can rewrite our equation as :

So; Given that:
The rope that is attached to the bucket is lm long and his arm is 75 cm long.
we have our radius r = 1 m + 75 cm
= ( 1 + 0.75 ) m
= 1.75 m
g = acceleration due to gravity = 9.81 m/s²
Replacing our values into equation (2) ; we have:

b) if he detaches the rope and spins the bucket by holding it with his hand ; then the radius = 0.75 m
∴

Answer:
The answer is below
Explanation:
Volt in physics is a term that is used to describe the unit of both electrical potential difference and electromotive force. In other words, it is a unit of measuring the voltage between two points. It is represented as "V".
The formula for Voltage is V=IR
Where V= Voltage, I = Current and R = Resistance.
Answer:
E. Some charges in the region are positive, and some are negative.
Explanation:
Electric potential is given as;

where;
W is the work done in moving a charge between two points which have a difference in potential
Q is quantity of charge in the given region
If the electric potential at a given point in the region is zero, then sum of the charges in the given region must be equal to zero. For the charges to sum to zero, some will be positive while some will be negative,.
Therefore, the correct statement in the given options is "E"
E. Some charges in the region are positive, and some are negative.
Colour: Colourless
Solubility in water: Slight
Freezing point: -218
I didn't get the boiling point