# Search results

1. ### Insulating spherical shell prob!

A small, insulating, spherical shell with inner radius a and outer radius b is concentric with a larger insulating spherical shell with inner radius c and outer radius d. The inner shell has total charge +q distributed uniformly over its volume, and the outer shell has charge -q distributed...
2. ### Point Charges

A point charge q1 -4 nC is at the point x = 0.600 m, y = 0.800 m, and a second point charge q2 +6 nC is at the point x = 0.600 m, y = 0. I need to calculate the magnitude of the net electric field at the origin due to these two point charges. |...
3. ### How would I calculate the magnitude of the electric field?

An electron is released from rest in a uniform electric field. The electron accelerates vertically upward, traveling 4.50 m in the first 3 us (microsecond??) after it is released. Part A What is the magnitude of the electric field? How would I calculate the magnitude of the electric field...
4. ### Charged Balls

There is a ball (A) is carrying a uniformly distributed unknown charge(wich may be zero) and an uncharged copper ball (D). A positive test charge (T) experiences highly attraction with ball (A) and (D). What is the nature of the force between balls A and D if they are brought very close...
5. ### Speed of Heartwall in body

A sound wave travels at a frequency 1.95 Mhz through a pregnant woman's abdomen and is reflected from the fetal heart wall of her unborn baby. The heart wall is moving toward the sound receiver as the heart beats. The reflected sound is then mixed with the transmitted sound, and 90.0 beats per...
6. ### Ear Damage from a Small Firecracker

Lets say there is a small firecracker that emits 1200 of peak power. What is the peak intensity B in decibels at a distance of 1 m from the firecracker? This is what i have tried: B = 10log(I/Io) I = 1200/pi Since I = power/area and the area is pir^2, pi(1m)^2 Io=( 10^-12...
7. ### Wire problem

A wire with mass (m) is stretched so that its ends are tied down at points a distance (s) apart. The wire vibrates in its fundamental mode with frequency (f) and with an amplitude at the antinodes of (A). [] How would I compute for the tension of the wire? since f =...
8. ### Probability and Multinomial Coefficients

An experimenter wishes to investigate the effect of three variables, pressure, temperature, and the type of catalyst, on the yield in a refining process. If the experimenter intends to use three temperature settings and three pressure settings and two types of catalysts, how many experimental...
9. ### Amplitude of a Wave

A large ant is standing on the middle of a circus tightrope that is stretched with (T) tension . The rope has mass per unit length (u). Wanting to shake the ant off the rope, a tightrope walker moves her foot up and down near the end of the tightrope, generating a sinusoidal transverse wave of...
10. ### Superposition of waves

How do I find the sum of these 2 waves, Asin(kx-wt) and Asin(kx+wt)? I have no clue how to add 2 sins with diffent phases. Thank you for your help!
11. ### Questions of a wave formula

Wave forumla: y(x,t) = Asin(kx-wt) [] Which variables (x, t, A, k, w) are independent? Would k be the only independent variable since it is a constant? However I am not too sure what exactly does the k represents. Can someone please clear that up for me? [] Which of...
12. ### Wave formula

For the traveling wave described by the formula y(x,t) = Asin(kx-wt) Then the wave is traveling in the +x direction. True or false? In the physics textbook I have, it describes a traveling wave by y(x,t) = Acos(kx-wt), using COS instead of SIN. Is there a difference between these 2...
13. ### How to calculate arctan(0) ?

What is arctan(0)?!?!?! I tired using my calculator (its a ti-83 plus) I hit [sec] button then [tan] then [ 0 ] and [ ) ] and it gives me 0 as answer It is in rad mode too (deg mode is same results) I tried using the google calculator and it gives me 0 also...
14. ### Converting rev to rad/s

Hello I have a question about converting rev to rad/s. If i had 1.13 revolutions for every 2.08s, how do I convert that into rad/s? 1.13rev/2.08s * 2pi ? Thank you for you help.
15. ### Change of Momentum

A 140 kg astronaut (including space suit) acquires a speed of 2.56 m/s by pushing off with his legs from a 1730 kg space capsule. The change in speed of the space capsule is .207 m/s. How would I find the change of momentum in the motion from above? m1 = 140 kg astronaut m2 = 1730 kg...
16. ### Work Kinetic E and Potential E

Can work change the energy of a system? Work cannot change the energy of a system. The above is false but i am not sure how to explain it Can someone please help me out? I understand that work = negative potential energy W = -U Also work = Change of Kinetic Energy W = (triangle)K
17. ### Flying car

[car] _o_o_____ .............| .............| 1.48 meters high ________|_______________________(must land here) .............|------21.1 meters--------| A stunt driver wants to make his car jump over a distance of 21.1 meters below a horizontal ramp With what minimum...
18. ### Rocket travelling up and down - kinematics

A model rocket has a constant upward acceleration of 40.0m/(s^2) while its engine is running. The rocket is fired vertically, and the engine runs for 2.59s before the fuel is used up. After the engine stops, the rocket is in free fall. The motion of the rocket is purely up and down. What...