Answer:
1. 18.25 m/s
2. 0 m/s
Explanation:
1.So the centripetal acceleration of the ball at this lowest point must be, taking gravity into account

The speed at this point would then be


2. Similarly, if T = mg, then the centripetal acceleration must be

As the ball has no centripetal acceleration, its speed must also be 0 as well.
Answer:Due to the pressure difference created by rotating fans.
Explanation:
In most of the vacuum cleaners, there is an area which is of disc shape and it is in right next to the motor. There are several fans within the disc that spin at a very high velocity.
The blades will push the air outside of the disk.There is no air in inside of the disc and air pressure creates which pushes air inside the disk to replace the missing air.
So motor is pushing the air outside and to maintain this pressure the air is pushing toward inside with dirt.
The best answer would be the 4th choice. "They help scientists explain concepts that are difficult to observe, this also covers the first answer which helps the scientist to answer complex questions. A scientific model is not used prove scientific laws as they may not always have all the data to prove so, instead it is used to allow them to explain better concepts revolving around science through research and may also allow them to predict results based on the accumulation of data and analyzing the trend of this resulting information.
Answer:
<em>The skydiver needs 0.71 seconds to reach 7 m/s</em>
Explanation:
<u>Free Fall Motion
</u>
When an object is dropped in free air (no friction) from a certain height h, it follows a free-fall motion, whose acceleration is due exclusively to gravity. The speed at a moment t when the object is dropped (from rest) is:

We need to find How long does the skydiver needs to reach 7 m/s. We solve for t



The skydiver needs 0.71 seconds to reach 7 m/s
Resistance of our body is given as

voltage applied across the body is

now by ohm's law current pass through our body is given by

![i = \frac{120}{30,000}[\tex][tex]i = 4 * 10^{-3} A](https://tex.z-dn.net/?f=i%20%3D%20%5Cfrac%7B120%7D%7B30%2C000%7D%5B%5Ctex%5D%3C%2Fp%3E%3Cp%3E%5Btex%5Di%20%3D%204%20%2A%2010%5E%7B-3%7D%20A)
So current from our body will be 4 * 10^-3 A