Physics Answers

A many-particle system

A system of four(4) free particles each has a mass m_i and initial position r_i and initial velocity v_i .

a) Describe your own four-particle system in detail.

b) Determine the position R_cm and velocity V_cm of the centre of mass of the system.

c) Determine the total linear momentum P_tot and the linear momentum P_cm of the centre of mass of the system.

d)Determine the total angular momentum L_tot and the linear momentum P_cm of the centre of mass of the system.

e) Discuss briefly about your answers in part b), c) and d).

A ball attached at the end of a string revolving in a horizontal circle of radius,R,at whirle a constant speed,v.The tension in the string is F.What is the force needed to increase the speed by 30%?

If two charges of magnitudes 2c and 5c are located at free space between 10 metres with the constant k=20 metre/farad, then the force between the charges will be

In one camera, the resistance of the bulb is 0.1 Ω, and the capacitor has a value of 4700 μF. How long will it take to discharge the capacitor to just 5% of its original voltage?

A lift and its passengers with a total mass of 500 kg accelerates upwards at 2ms^-2 as shown.

Assume that g = 10 ms^-2.

7200 J of energy is required to run a light bulb for a minute. What is the power of the light bulb?

14 Study of a recording The recording of the movement of the center of inertia of a mobile on a cushion table da.  horizontal gave the following result (full size).  The time r between two pointers is gp ms.  20

a) Is the mobile pseudo-isolated?  b) Determine and represent the velocity vectors respectively at points G, G2, G3 and c) Determine the acceleration vectors respectively at G, and G. Compare these two d) Determine the direction and direction of the resulting force exerted on  the cellphone.  e) Is this force constant?  To justify.  accelerations.

Q1. A liquid turns into a gas faster if the size of the surface area of the liquid is... what?

A Christmas ball in a shape of a hollow sphere is hung from the tree by a piece of thread attached to the surface of

the ball. The mass and radius of the ball are 0.105kg and 0.12m, respectively. What will be its period of oscillation

when slightly displaced from its equilibrium position? (Hint: I =5/3 mr^2)

Explain resitivity in simple words