Physics Answers

Calculate the electric flux through a rectangular surface of dimensions 20cm × 10cm, placed with its positive normal making an angle of 30° with a uniform electric field of 30 × 10^-3 N/C.

A body having a net charge of 37 µC placed in a uniform electric field of 750 N/C. What is the mass of the body if it lies on the surface in the field?

Please give me the full solution, thank you so much.

The radius of the outer sphere of a spherical capacitor is five times the radius of its 

inner shell. What are the dimensions of this capacitor if its capacitance is 5.00 pF?

A positive charge, q=+20 nC, is on the y-axis at y +4.00 cm. (a) Determine the magnitude and direction of the electric field at the origin (b) What will be the magnitude and direction of the electric field at the origin of the charge is -20 nC?

Suppose a friend asks you to explain how electric potential relates to potential energy. Write a brief explanation that you could use to explain this concept to a friend who does not understand the relationship between two concepts

In a certain region an electric potential V is present. An unknown charge Q is moved around this region between points at potential difference ΔV. A physicist measures the change in the potential energy ΔU as the charge is moved. The table below shows the data of the measurements. The unit for ΔV are MV (mega-Volts), the units for ΔU are kJ (kilo-joules).

ΔV

57.1

29.9

16.7

9.97

8.55

8.32

6.52

6.87

ΔU

362.8

157.6

124.3

55.3

48.8

53.9

37.9

47.3

You want to find the value of the unknown charge Q in mC. Since ΔU = QΔV make the plot 𝑦=𝑚𝑥 where 𝑦=𝛥𝑈 and 𝑥=𝛥𝑉. Use Excel, calculator or whatever you prefer. From the slope of the plot, calculate Q.

1.) The height from the ground to point A is 10m, from ground to point B is 6m, and from ground to point E is 1m. If the ball weights 100 N. What is the change in energy of the ball from point x to point y?

a. 10,000 J

b. 100 J

c. 0 J

d. 1000 J

2.) The height from the ground to point A is 10m, from ground to point B is 6m, and from ground to point E is 1m. If the ball weights 100 N, and its speed doubles as it reaches point C, what is its speed at point C?

a. 0 m/s

b. 8.94 m/s

c. 4.47 m/s

d. 34.64 m/s

A 6-footer Pedro lifted a 50-kg sack of rice and put it on top of his head. How much power does Pedro have if he was able to lift the sack in 1 second?

a. 1000 J/s

b. 9000 J/s

c. 100 J/s

d. 900 J/s

A sound wave of frequency 300Hz travels with speed 340 m/s along the negative x-direction . Each point of the medium moves up and down through a total distance of 5.0 mm. Determine the necessary parameters to represent the wave mathematically.