1. Person A has twice the mass of person B. If they are placed at both sides of the seesaw and are at equilibrium, then

A. person a is half as far from the folcrum as person B

B. person A is 1/4 as far from the folcrum as person B

C. person A is 4 times farther away from the folcrum as person B

D. person A is twice as far away from the folcrum as person B

Wanted to understand the physics behind usage of passive antennae and matched load combination, to absorb, control and reduce the Electromagnetic-Field (s.a. due to microwave radiation from cellular phone towers), within a confined area (s.a. a room). Also, does the shape / size / material used for the antenna have a role to play ? If this kind of absorption does work, what might be the range / shape of the area that such a device can reduce / remove the radiation from ?

I have come across EMF shielding/reduction solutions which use such combination, and also some sort of Faraday-cage effect to keep out EMF radiation, which require "grounding". Are these two based on similar / related principles ?

Finally, I read in an article that not grounding the Faraday-cage (or the metallic protective shield), results in the metal starting to becoming radioactive, or maybe even emit X-rays.

Please do excuse the rather layman approach to the questions, a dumbed-down but factual (i.e. can be backed by theory and empirical data, if required) explanation would be highly appreciated.

At the beach, some waves with wavelength of 100 m propagate towards the shore at a speed of 12.5 m/s. (c) Does the engine sound higher- or lower-pitched to someone standing on the shore, compared with the experience of people on the boat?

(a) Calculate the frequency that boat anchored near shore bobs up and down as the waves roll in.

(b) At what frequency the boat would bob up and down with if it were headed away from the shore at a speed of 4.8 m/s?

(c) At what frequency the boat would bob up and down with if it were headed toward the shore at a speed of 4.8 m/s?

As shown in the figure below, two blocks (m₁ and m₂) are each released from rest at a height of  

h = 4.68 m

on a frictionless track and when they meet on the horizontal section of the track they undergo an elastic collision. If

m₁ = 2.50 kg

and

m₂ = 4.05 kg,

determine the maximum heights to which they rise after the collision. Use the coordinate system shown in the figure.

A 2.90-cm-high object is situated 11.6 cm in front of a concave mirror that has a radius of curvature of 11.2 cm. Calculate (a) the location and (b) the height of the image.

During the middle of a family picnic, Barry Allen received a message that his friends Bruce and Hal needed to be saved. Barry promised his wife Iris that he would be back in exactly 5 minutes. From that that picnic location, Barry runs at a speed of 600 m/s for 2 minutes at a heading of 35° north of west to save Bruce. He then changed his heading to 30° west of north, slows down to 400 m/s and runs for 1 minute to save Hal. (The changes in speed are essentially instantaneous and not part of solving this problem). (a) Draw a physical representation of the displacement during Barry’s full trip. (b) Use the Related Quantities sense-making technique to compare Barry’s total distance traveled to the magnitude of his displacement. (c) What average velocity (magnitude and direction) does Barry need to return back to the picnic in order to keep his promise to Iris?

The visible spectrum is in the 400-700 nm range, and contains about 40% of the sun’s radiation intensity. Using the Planck Distribution, write an integral expression that can be evaluated to give this result (do not evaluate the integral).

What is the energy released in this β + nuclear reaction 29 16 S → 29 15 P + 0 1 e ? (The atomic mass of 29 S is 28.996615 u and that of 29 P is 28.9818 u)

13.3 MeV is incorrect

An object with a charge of -3.2 ?C and a mass of 1.6×10^?2 kg experiences an upward electric force, due to a uniform electric field, equal in magnitude to its weight.

A) Find the magnitude of the electric field.

Answer: E = 4.9×10⁴ N/C

B) Find the direction of the electric field.

Answer: Downward

C ) If the electric charge on the object is doubled while its mass remains the same, find the direction and magnitude of its acceleration.

Express your answer using three significant figures.

D) If the electric charge on the object is doubled while its mass remains the same, find the direction and magnitude of its acceleration.

A person drops a cylindrical steel bar (Y = 7.00 × 1010 Pa) from a height of 1.40 m (distance between the floor and the bottom of the vertically oriented bar). The bar, of length L = 0.780 m, radius R = 0.00650 m, and mass m = 1.600 kg, hits the floor and bounces up, maintaining its vertical orientation. Assuming the collision with the floor is elastic, and that no rotation occurs, what is the maximum compression of the bar? In meters

I need to write a Scientific paper on

"Kinetics concepts and electric and magnetic phenomena"

1. Discuss the applications of these phenomena to everyday life and modern technology and medicine.

A subatomic particle undergoes a one-dimensional elastic collision with an initially stationary atom. What percentage of the subatomic particle's initial kinetic energy is transferred to kinetic energy of the atom? (The mass of the atom is 1190 times the mass of the subatomic particle.)

When landing poorly from a jump, your leg is likely to break at a point just above the ankle where the cross-sectional area of the bone (the tibia) is smallest. The tibia has a radius of 0.70.7cm. A bone will fracture when the compressive stress on it exceeds 130130MPa.

Your intrepid physics instructor (mass 6060kg) jumps from a desktop of height 1.21.2m onto a concrete floor, landing evenly on two legs. How much should she bend her knees to avoid breaking bones? Specifically, what is the minimum stopping distance dd such that the stress on the tibia during her landing is sufficiently low that it will not break? Give your answer in cm.

Notice that landing with stiff knees greatly decreases this stopping distance and is thus a really bad idea.