Absolutely no idea how to solve these

[evildarklord1985]

I'm asking you guys for serious help in these homework for Engineering physics.

1) Protons having a kinetic energy of 5.00 Me are moving in the positive x direction and enter a magnetic field B = 0.050k (T) directed out of the plane of the page and extending from x=0 to x=1.0 m . Calculate the y component of the proton momentum as they leave the magnetic field.

2) A long piece of wire of mass 0.1kg and length 4.0m is used to make a square coil 0.10m on a side. The coil is hinged along a horizontal side, carries a 3.4 A current, and is placed in a vertical magnetic field of magnitude 0.010 T. Determine the angle that the plane of the coil makes with the vertical when the coil is in equilibrium.

3) A uniform magnetic field of magnitude 0.150 T is directed along the positive x axis. A positron moving at 5.0 x 10^6 m/s enters the field along a direction that makes an angle of 85 degree with the x axis. The motion of the particle is expected to be a helix. Calculate the pitch p and the radius of the trajectory

All these problems are from Engineering Physics , Serway textbook...I stayed up a whole night already, but still couldn't figure out anything...

 

[berkeman]

Thread moved to the homework forums.

Welcome to the PF, evildarklord (interesting handle). You need to show some of your own work in order for us to help you (PF rules).

On -1- What equation governs the forces on a charged particle in a magnetic field?

-2- What equations describe the forces on a wire carrying a current?

-3- See -1- above.

 

[kyle8921]

I understand that sometimes complex problems can be challenging and frustrating to solve. I suggest breaking down each problem into smaller parts and using known equations and principles to approach each part.

For the first problem, you can use the equation for the magnetic force on a charged particle (F = qvB) to calculate the force on the protons as they enter the magnetic field. From there, you can use the equation for momentum (p = mv) to calculate the momentum in the y direction.

For the second problem, you can use the equation for the magnetic torque on a current-carrying loop (τ = IABsinθ) to calculate the torque on the coil. Set this equal to the torque due to gravity (mgLsinθ) and solve for the angle θ.

For the third problem, you can use the equation for the radius of a helix (r = mv⊥/qB) to calculate the radius of the positron's trajectory. The pitch can be calculated using the equation p = 2πr.

I would also recommend reviewing the relevant chapters in your textbook and seeking help from your professor or classmates if you are still struggling. Remember to approach each problem step by step and use the equations and principles you have learned. Good luck!