Answer:
72 volts.
Explanation:
To solve this, we have to use the Ohm's law.
The ohm's law tells us that the voltage drop of a resistor is directly proportional to the current applied to the conductor.

in this case the current is 1.8 amps and the resistor is 40 ohm

so
.
Answer:
Explanation:
A )
At the bottom of the circle , the potential energy of the stopper is converted into kinetic energy
1/2 m V² = mg x 2r + 1/2 mv²
m is mass of stopper , V is velocity at the bottom , r is radius of the circular path which is length of the string , v is velocity at the top
1/2 V² = g x 2r + 1/2 v²
V² = g x 4r + v²
V² = 9.8 x 4 + 8²
V² = 103.2
V = 10.16 m/s
B )
If T be the tension at the top
Net downward force
= mg + T . This force provides centripetal force for the circular motion
mg +T = mv² / r
T = mv²/r -mg
= m ( v²/r - g )
= .005 ( 8²/1 -g )
= .005 x 54.2
= .27 N .
C ) At the bottom
Net force = T - mg , T is tension at the bottom , V is velocity at bottom
T-mg = mV²/r
T = m ( V²/r +g )
= .005 ( 10.16²/1 +9.8)
= .005 x 113
= .56 N .
Answer:


Explanation:
Height Of the watermelon when it is dropped is given as

time of fall under gravity

now if water melon start from rest then we have

acceleration due to gravity for watermelon

now we need to find the final speed of watermelon

so we will have


Answer:
Force on the proton will be 
Explanation:
We have given speed of proton is 20.3% of speed of light
Speed of light 
So speed of proton 
Magnetic field B = 0.00629 T
Charge on proton 
Angle between velocity and magnetic field 
Force on the proton is equal to 
Answer:
The correct option is : Their atoms have eight electrons in their valence shells, so noble gases are very unreactive.
Explanation:
The octet rule state that atoms tend to complete their last energy levels with eight electrons, and that this configuration make them very stable and unreactive.
Noble gases are characterized as unreactive atoms, and this is associated with the fact that they have a complete valence shell, it means that they have eight electrons on it (they follow the octet rule).
Atoms with less electrons on their valence shells tend to react with another atom, forming bonds, to complete their valence shells (with eight electrons).