Physics Answers

The force of attraction between Anna and her 40 kg classmate, Maria is 3.00 x 10 -8 N.

Determine the mass of Anna if they are 2.0 m away from each other.

(A) Explain how pure metal and a semi conductor can be distinguished through the effect of temperature on their electrical resistance

(B) explain what is meant by (I) an n-semi conductor (ii) a p-semiconductor

(C) state two advantages and one disadvantage of a junction diode over a thermionic valve

A block of concrete weights 900N and its base is a square of side 3m. What pressure does the block exert on the ground?

Estimate the wavelength of x-rays emitted by platinum as an electron falls from n = 2 to n = 1. Platinum has Z = 78. n

Ganymede is one of the moons of Jupiter. Ganymede’s period of revolution around Jupiter is 7.16 Earth days and an orbital radius of about 1.07x10^9. What is the mass of Jupiter?

(a) Find the volume of water in a swimming pool with vertical ends and sides. The length measured at the water line is 50 ft. and the breadth is 20 ft. The bottom of the swimming pool is a plane slopping gradually downward so that the depth of the water at one end is 8 ft. and at the other end is 4 ft.

(b) If the sides, ends, and bottom of the swimming pool are constructed of tile blocks whose glazed surface dimensions are 3 in. by 6 in., and if the ends and sides of the pool extend 2 ft. above the water level, find the number of blocks used if 1/20 of the surface area is covered by sealing material.

A contractor agrees to build a dam 180ft long and 20ft high, 12ft wide at the bottom and 8ftwide at the top for $9.75 a cubic yard. Find his profit if his costs were $10000?

a concrete octagonal pier of height 10ft. is to resurfaced. if each of the base edges is 1ft. how many square ft. of surfacing will be required?

a 50 kg sled is pulled along a level surface at constant velocity by a constant force of 200n at an angle of 30° what is the coefficient of friction between the sled and the surface

the water flows in the channel 844 mm x 586 mm at the rate of 8 m/sec. What is the volume flow in ft^3/sec?