Answer:
60words/minute
Explanation:
If Sunitha can type 1800 words in half an hour, this can be expressed as;
1800 words = 30 minutes
To get her typing speed per minute, we will use the formula
Speed = Number of words/Time used
Typing speed = 1800/30
Typing speed = 60words/minute
Hence her typing speed in words per minute is 60words/minute
█ Answer <span>█
</span><span>The energy from our sun is produced by fusion of hydrogen.
Choice D is the answer.
</span><span>Hope that helps! ★ If you have further questions about this question or need more help, feel free to comment below or leave me a PM. -UnicornFudge aka Nadia
</span>
(a) The force exerted by the electric field on the plastic sphere is equal to
![F=qE](https://tex.z-dn.net/?f=F%3DqE)
where
![q=-3.4 nC=-3.4 \cdot 10^{-9} C](https://tex.z-dn.net/?f=q%3D-3.4%20nC%3D-3.4%20%5Ccdot%2010%5E%7B-9%7D%20C)
is the charge of the sphere and E is the strength of the electric field. This force should balance the weight of the sphere:
![F=mg =0.9 g](https://tex.z-dn.net/?f=F%3Dmg%20%3D0.9%20g)
where m is the mass of the sphere and g is the gravitational acceleration.
Since the two forces must be equal, we have:
![qE=mg](https://tex.z-dn.net/?f=qE%3Dmg)
and so we find the intensity of the electric field
![E= \frac{mg}{q}= \frac{0.9 \cdot 9.81 m/s^2}{3.4 \cdot 10^{-9} C} =2.6 \cdot 10^9 N/C](https://tex.z-dn.net/?f=E%3D%20%5Cfrac%7Bmg%7D%7Bq%7D%3D%20%5Cfrac%7B0.9%20%5Ccdot%209.81%20m%2Fs%5E2%7D%7B3.4%20%5Ccdot%2010%5E%7B-9%7D%20C%7D%20%3D2.6%20%5Ccdot%2010%5E9%20N%2FC%20)
(b) Now let's find the direction of the field. The electric force must balance the weight of the sphere, which is directed downward, so the electric force should be directed upward. Since the charge is negative, the force is opposite to the electric field direction, and so the direction of the electric field is downward.