27% helium and 71% hydrogen
The displacement is just the distance between the starting point and the
ending point, and you don't care about the route taken or the actual distance
covered along the way.
This can bite you sometimes. For example, some day you'll be given the
diameter of a circle, and you'll be asked for the displacement of an ant that
walks around the circle 17 times and finally stops at the same place it
started from. You might go to work calculating the circumference of the
circle and multiplying it by 17. But if you think about it first, you realize that
if the ant ends up at the place he started from, then his displacement is zero.
A 500 g ball swings in a vertical circle at the end of a 1.4-m-long string. when the ball is at the bottom of the circle, the tension in the string is 18 n.
The electric field E of a charge is defined as E=F/Q where F is the Coulomb force and Q is the test charge.
E=(1/Q)*k*(q*Q)/r², where k=9*10^9 N*m²/C², q is the point charge, Q is the test charge and r is the distance between the charges.
So E=(k*q)/r²
When we input the numbers we get that electric field E of a point chage q is:
E=(9*10^9)*(5.4*10^-8)/0.2²=486/0.04=12150 N/C.
This is roughly E=12000 N/C =1.2*10^4 N/C
The correct answer is B.
The SI unit of energy is the Joule .
Any kind of energy ... electrical, mechanical, nuclear, solar,
wind etc. It's easy to change from one form to another ... we
do it every day ... and they all have the same unit.
