Answer:
Around 2.8212 sec
Explanation:
Given the eqn x=1/2at^2+vot
your vo=0
39=1/2(-9.8)t^2
=7.95=t^2
=2.82sec
Answer:
(a) 
(b) 
(c) 
Explanation:
First change the units of the velocity, using these equivalents
and 

The angular acceleration
the time rate of change of the angular speed
according to:


Where
is the original velocity, in the case the velocity before starting the deceleration, and
is the final velocity, equal to zero because it has stopped.

b) To find the distance traveled in radians use the formula:


To change this result to inches, solve the angular displacement
for the distance traveled
(
is the radius).


c) The displacement is the difference between the original position and the final. But in every complete rotation of the rim, the point returns to its original position. so is needed to know how many rotations did the point in the 890.16 rad of distant traveled:

The real difference is in the 0.6667 (or 2/3) of the rotation. To find the distance between these positions imagine a triangle formed with the center of the blade (point C), the initial position (point A) and the final position (point B). The angle
is between the two sides known. Using the theorem of the cosine we can find the missing side of the the triangle(which is also the net displacement):


Here is the energy that is left after the quantity of energy is transformed: 750 j of electrical energy is changed into 400 j of kinetic or mechanical energy, which is then turned into 0.32 j of efficient energy.
To run the fan, electrical energy is utilized.
Here, under the specified circumstances, 750 J of electrical energy is utilized to operate the fan, which is transformed into 400 J of kinetic energy. As a result, 350 J of energy is wasted due to various frictional and resistive losses.
Therefore, we may conclude that only 400 J of the 750 J available energy is used to power the fan, with the remaining energy being wasted as a result of friction.
Additionally, we can state that this fan's effectiveness will be
n = Useful ÷ Total
n = 400 ÷ 750
n = 8 ÷ 25
n = 0.32
Learn more about energy at
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Hi there!
Great question!
Basketballs have air inside them. A special pump is used to insert the air. That's why you can lift the basketballs off the ground easily. If it was a solid, though, you'd hardly be able to lift the ball up! Basketballs can float, too, because anything with air inside can float. If it were solid, it would sink in the water easily.
Hope this helps! :D
Answer:
n = 756.25 giga electrons
Explanation:
It is given that,
If the charge on the negative plate of the capacitor, 
Let n is the number of excess electrons are on that plate. Using the quantization of charges, the total charge on the negative plate is given by :

e is the charge on electron

or
n = 756.25 giga electrons
So, there are 756.25 giga electrons are on the plate. Hence, this is the required solution.