Physics Answers

The lenght of a string between a kite and Point A on the ground is 442meter. If the height of the kite is 42metwr from the ground.Find the horizontal angle and distance of the kite from point A.

Lesson: Capacitance & Capacitors

Solve the problem:

The two metal objects in the figure below have net charges of +70 pC and -70 pC, which result in a 20 V potential difference between them. (a) What is the capacitance of the system? (b) if the charges are changed to +200 pC and -200pC, what does capacitance become? (c) What does the potential difference become?

Show that superposition principle does not hold for a non linear DE like; d²x/d²t + cx² = 0 where c is constant.

a force B is required to bring a box with a mass of 2.5 kg to the height of 3 m at an acceleration of 6. BY assuming it is smooth pulley system ,find the magnitude of force B 

An automobile engine has an efficiency of 20% and produces 6000 J work. Find

the heat rejected by the engine. 

​(I) Four point charges are located at the vertices of a square with side L.

We give q2 ​= q3 ​= Q and q1​= q4 ​= −2Q.

​Determine the resulting electric field​ (a) at point A​,

in the center of the square; (b) at point B

 a) State Snell’s law in equation form.                                                          

b) Light crosses from air to water. The angle of incidence is 75⁰. Draw a schematic diagram of this

event.                                     

 c) Calculate the angle of refraction for the event in part b). Take the refractive index of water to be 4/3.   

1)   A glass window is exactly 20 cm by 30 cm at 10 ⁰C. By how much would its area increase in cm² when

its temperature is 40 ⁰C? Take the linear expansivity of glass to = 9 X 10^-6 / C⁰.

1)   Compare the mercury-in-glass thermometer to the alcohol-in-glass thermometer with respect to: safety,

operating range and sensitivity.

A box with a weight of 1260 N was dragged across the horizontal floor by a man by pulling a rope that is tied on the box. The man exerts a force of F= 485N on the rope, which is inclined at an angle of = 25o and the floor exerts a friction force of 98N on the box.

Find the following:

a. Draw the free-body diagram of the box.

b. The magnitude of the acceleration of the box.

c. Find the coefficient of friction

d. Find the normal force by the floor to the box.