Electric fields/angle of deflection problem

AI Thread Summary
Ink-jet printers deflect ink droplets using an electric field to ensure accurate placement on paper. The problem involves droplets with a mass of 1 x 10^-10 kg, a charge of 2.1 pC, and a speed of 12 m/s passing through a 97-kN/C electric field, resulting in a 10º deflection angle. The challenge lies in correctly applying kinematic equations to account for the angle of deflection, as initial assumptions treated it incorrectly. The relationship between time and distance must be established using L tan(10°) and substituted into L = Vt to find the length of the field region. Understanding the angle as the final deflection point is crucial for solving the problem accurately.
oksanav
Messages
66
Reaction score
0
Here's the problem:
Ink-jet printers work by deflecting moving ink droplets with an electric field so they hit the right place on the paper. Droplets in a particular printer have mass 1 x 10^-10 kg, charge 2.1 pC, speed 12 m/s, and pass though a uniform 97-kN/C electric field in order to be deflected through a 10º angle. What is the length of the field region?

My teacher gave us this problem and there's only one like it in the book, and in that one angles aren't involved. My group worked it in class yesterday and he said we had the right idea but were misusing the angle. Our idea was to use kinematic equations, solve the y component for t and plug into the x component. The problem is we don't know what to do with the angle. We knew that the path starts with an angle of zero and is eventually 10º , but forgot this and were treating the angle as the initial angle. I just don't understand where the angle starts or how to treat it. Can I treat it as a triangle and somehow find the components of r(t)? Sorry to ramble on, I'm just frustrated.
 
Physics news on Phys.org
Well, one is given, the speed of 12 m/s, and one has the relationship the t = L/V, or L = Vt

In the same time, t, the droplet must accelerate to a distance, which is given by L tan(10°). One must fine the relationship between t and L tan(10°), or rather t in terms of L tan(10°), and substitute into L = Vt.

The angle between the axis of the inkjet and the spot on the paper must by 10°. That is the deflection when contact by ink drop on paper has been made.
 
Last edited:
Thread 'Collision of a bullet on a rod-string system: query'
In this question, I have a question. I am NOT trying to solve it, but it is just a conceptual question. Consider the point on the rod, which connects the string and the rod. My question: just before and after the collision, is ANGULAR momentum CONSERVED about this point? Lets call the point which connects the string and rod as P. Why am I asking this? : it is clear from the scenario that the point of concern, which connects the string and the rod, moves in a circular path due to the string...
Thread 'A cylinder connected to a hanged mass'
Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
Back
Top