Electricity-sweater physisc problem

Thread starter lauralovesyou
Start date Apr 18, 2010

AI Thread Summary

When removing a wool sweater, static electricity is generated due to the friction between the sweater and hair, causing electrons to transfer from one material to the other. This transfer results in the sweater becoming negatively charged and the hair positively charged. The opposite charges create an attractive force, pulling the hair towards the sweater. The phenomenon is a classic example of electrostatic attraction, illustrating the principles of charge transfer and electron movement. Understanding this interaction highlights the role of static electricity in everyday experiences.

Apr 18, 2010

lauralovesyou

Sometimes when you are taking off a wool sweater by pulling it over your head, you find that your hair is attracted to the sweater. Explain why this is so by referring to the movement of electrons.

Physics news on Phys.org

Apr 18, 2010

thebigstar25

maybe you want first to share with us what answer you should provide here :) ..

Thread 'Errors and significant figures'

I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19. For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...

View full post »

Thread 'Calculation of Tensile Forces in Piston-Type Water-Lifting Devices at Elevated Locations'

Figure 1 Overall Structure Diagram Figure 2: Top view of the piston when it is cylindrical A circular opening is created at a height of 5 meters above the water surface. Inside this opening is a sleeve-type piston with a cross-sectional area of 1 square meter. The piston is pulled to the right at a constant speed. The pulling force is（Figure 2）： F = ρshg = 1000 × 1 × 5 × 10 = 50,000 N. Figure 3: Modifying the structure to incorporate a fixed internal piston When I modify the piston...

View full post »

Thread 'A cylinder connected to a hanging 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...

View full post »