Magnetisim Problem Just need an Equation.

[Fused]

Here's the problem:

A proton follows a spiral path through a gas in a magnetic field of 0.010 T, perpendicular ot hte plane of the spiral. In two successive loops at points P and Q, the radii are 1.0 mm and 8.5 mm respectively. Calcualte hte hcnage in the kinetic energy of hte proton as it travels from P to Q/

I just need a general direction to go in and maybe what formulas to use. Since we are trying to find kinetic energy, would I be using the (mv)^2/r for centripetal force?

 

[stunner5000pt]

Since the measured radii are iven you can assume taht the proton moved inb perfect circles given those radii.

so since it is moving in a perfect circle the centripetal force = magnetic force
m \frac{v^2}{r} = qvB sin \theta
where theta is the angle between the particle and the field (given to you)

solve for the unknown in that equation each time then find the change in kinetic energy

 

[thepatientmental]

To solve this problem, you can use the formula for the magnetic force on a charged particle moving through a magnetic field, which is F = qvB, where q is the charge of the particle, v is its velocity, and B is the magnetic field strength. You can also use the formula for centripetal force, F = mv^2/r, where m is the mass of the particle, v is its velocity, and r is the radius of its circular motion.

First, we need to find the velocity of the proton at points P and Q. We can use the centripetal force formula to solve for v, since we know the radius and the magnetic force acting on the proton. So, at point P, we have:

F = mv^2/r
0.010 T = (1.6 x 10^-19 C)vB/1.0 x 10^-3 m

Solving for v, we get v = 1.0 x 10^5 m/s.

At point Q, we have:

F = mv^2/r
0.010 T = (1.6 x 10^-19 C)vB/8.5 x 10^-3 m

Solving for v, we get v = 1.2 x 10^4 m/s.

Now, to find the change in kinetic energy, we can use the formula KE = 1/2mv^2. So, at point P, the kinetic energy is:

KE = 1/2(1.6 x 10^-27 kg)(1.0 x 10^5 m/s)^2 = 8.0 x 10^-19 J

At point Q, the kinetic energy is:

KE = 1/2(1.6 x 10^-27 kg)(1.2 x 10^4 m/s)^2 = 1.44 x 10^-20 J

Therefore, the change in kinetic energy is:

ΔKE = 8.0 x 10^-19 J - 1.44 x 10^-20 J = 7.856 x 10^-19 J

So, the change in kinetic energy of the proton as it travels from P to Q is 7.856 x 10^-19 J.