Physics Answers

1. A carbon wire with a 3 mm diameter has a resistance of 100 ohms. How long is the wire?

2. A 200 m long aluminum wire has the same resistance and cross sectional area as a carbon wire. What is the length of the carbon wire?

3. A wire made of an unknown substance has a resistance of 125 mΩ. The wire has a length of 1.8m and a cross-sectional area of 2.35 x 10^-5 m^2. What is the resistivity of the substance from which the wire is made? Give your answer in scientific notation to one dicimal place.

In order to get his car out of the mud, a man ties one end of a rope to the front bumper and

the other end to a tree 15 m away, as shown below. He then pulls on the center of the rope

with a force of 400 N, which causes its center to be displaced 0.30 m, as shown. What is the

force of the rope on the car?

A high-speed electron having a mass of 9 x 10^ -31 kg is moving at right angle to 0.75-T magnetic field and has a speed of 2.5 x 10^7m/s. What is the size of the force acts on the high-speed electron? What is the magnitude of acceleration of the particle?

A small sphere of charge +6 x 10^-6C is suspended by a string of negligible mass. A charge of -9 x 10^-6 C is placed directly to the right of the sphere and 0.22m away from it. The string is deflected 5° from the vertical. Find the tension in the string.

A 90000 lbs truck is braked to a stop in 95 ft. from an initial speed of 95 ft/s . How

much force was required ?

What are the mole fractions of hydrochloric acid (HCI) and water in a 20% (w/w) aqeous HCl solution?

A puck with a mass of 0.170 kg has a velocity of + 90.0 km/h. The momentumof the puck is

A closed coil of 40 turns and of area 200 cm2, is rotated in a magnetic field of flux density 2 Wb m-2. it rotates from a position where its plane makes an angle of 30° with the field to a position perpendicular to the field in atime 0.2 sec. Find the magnitude of the emf induced in the coil due to its rotation.

An electron is accelerated from rest through a potential difference is 15V.What is the change in electric potential energy of the electron?

An average human weights about 650 N.if two such generic humans each carried 1.0 coulomb of excess charge,one positive and one negative. How far apart would they have to be for the electric attraction between them to equal their 650-N weight