# Recent content by Sixty3

1. ### Electric field on a surface

Homework Statement A metallic surface is placed in an electrostatic field. Derive an expression for the electric field on the metal surface. Homework Equations \oint \underline{E} \cdot d\underline{A}=\dfrac{q_{enc}}{\epsilon_0} The Attempt at a Solution My initial thought was to set up a...
2. ### Uniform magnetic field and electric field

I am lost with this question, but to go about finding the velocity at time t I think it's v=q/m (integral)[E+vxB]dt, it's just the limits of integration I'm not able to find. Thanks for replying.
3. ### Uniform magnetic field and electric field

I misunderstood the question, but I need to find the magnitude of the velocity after 'c' revolutions.
4. ### Uniform magnetic field and electric field

Homework Statement How would you find the period of a charged particle in an uniform electric and magnetic field? The charged particle has velocity that is perpendicular to the magnetic and electric field (which are directed in the x-axis). Homework Equations F=q(E+vxB) The Attempt...
5. ### First Law of Thermodynamics

Homework Statement 5 litres of an ideal gas which is initially at 300K and 10atm, and is expanded to a final pressure of 1atm. Find work done, change in internal energy, heat absorbed and change in enthalpy of the system if the process is isothermal and reversible. Homework Equations...
6. ### How do I calculate the Velocity when only given the force and weight?

The elastic potential energy is given by PE=\frac{1}{2}kx^2 The potential energy will be converted to kinetic energy given by KE=\frac{1}{2}mv^2
7. ### Relativity, time difference from two planets

Homework Statement Two planets A and B have relative velocities 0.7c. They can observe the birth of two stars, C and D. According to planet A, star D was born 10 years before star C was born. According to planet B, star C was born 20 lightyears farther than star D. What is the time...

Homework Statement Two spaceships A and B are launched from a point X, in opposite directions. At time t=15 minutes, spaceship A crashes. The velocity of the spaceships relative to X is 1.3x10⁸m/s. How far did the collision happen from B, as observed by astronauts on the spaceship...
9. ### Constant acceleration

You are using the correct equation, but your values for 'a' and 't' are wrong. The acceleration of the ball is given to you in the question, so you don't need to use 9.81m/s². And also the time stated in the question is 7.72s.
10. ### How to answer question on momentum?

Homework Statement I am not sure wether I should take the value of velocity as a negative or positive in momentum questions. A cart (cart 1) of mass 5kg is travelling to the right with a velocity of 5m/s and another cart (cart 2) of mass 5kg is travelling to the left with a velocity of 1m/s...
11. ### Total energy of an object.

Homework Statement If a question asks to calculate total energy of an object that does have a horizontal velocity (constant, air resistance ignored), and it is at it's highest point so it's vertical velocity is zero. I need to know how you'd calculate the total energy of this object...
12. ### First Law of Thermodynamics

Homework Statement I am looking into the first law of thermodynamics. But I'm not sure with some parts. Homework Equations dU=Q-W What does it mean when U Q and W are negatives. Also solids with W=0 The Attempt at a Solution So the equation will change to -U=-Q+W Does it lose it's...
13. ### Wave question

Homework Statement a) A microwave transmitter T and receiver R are placed side by side facing two sheets of material M (aluminium) and N (hardboard). A very small signal is registered by R; what can you deduce about the experimental set up? b) When M is moved towards N a series of maxia and...