South
Explanation:
The magnetic force F on a point charge moving with a velocity v in the presence of a magnetic field B is given by

and according to the right-hand rule, an upward magnetic force on a proton moving westward is only possible if the magnetic field is directed southward.
Friction is the force that opposes motion.
<h3>What is friction?</h3>
The term friction refers to the force that hinders the movement of a surface over another. The frictional force depends on the nature of the surfaces in contact.
1) The two forces acting on the ball during the frictional force are the forward force and the frictional force.
2) The ball takes more time to roll down the incline in the presence of the cloth because of the increase in friction of the surface.
3) The students repeated the investigation there times in order to ensure accuracy of the results.
4) The energy of the ball changes from potential energy at the top of the ramp to kinetic energy as it rolls down the ramp.
Learn more about frictional force: brainly.com/question/1714663
3 trillion= 3X10^<span>12
5 thousanths= 5X10^-3
730000000000000= 7.3X10^14
0.000000000082= 8.2X10^-11</span>
Let l = Q/L = linear charge density. The semi-circle has a length L which is half the circumference of the circle. So w can relate the radius of the circle to L by
<span>C = 2L = 2*pi*R ---> R = L/pi </span>
<span>Now define the center of the semi-circle as the origin of coordinates and define a as the angle between R and the x-axis. </span>
<span>we can define a small charge dq as </span>
<span>dq = l*ds = l*R*da </span>
<span>So the electric field can be written as: </span>
<span>dE =kdq*(cos(a)/R^2 I_hat + sin(a)/R^2 j_hat) </span>
<span>dE = k*I*R*da*(cos(a)/R^2 I_hat + sin(a)/R^2 j_hat) </span>
<span>E = k*I*(sin(a)/R I_hat - cos(a)/R^2 j_hat) </span>
<span>E = pi*k*Q/L(sin(a)/L I_hat - cos(a)/L j_hat)</span>
please, give the question properly.