Physics Electrostatics Level: High School
Coulomb’s Law
Two charges attract each other with a force of 1.0 N . What will be the force if the distance between them is reduced to one-ninth of its original value ?
Physics Heat & Thermodynamics Level: High School
Heat Engine
An engine has an efficiency of 60% and produces 6700 J of work . Determine each of the following .a) the input heat
b) the rejected heat
Physics Heat & Thermodynamics Level: High School
First Law of Motion
Three moles of a monatomic ideal gas are heated at a constant volume of 1.30 m^3 . The amount of heat added is 4.50 x 10^3 J .a) What is the change in the temperature of the gas ?
b) Find the change in its internal energy ?
c) Determine the change in pressure .
Physics Heat & Thermodynamics Level: High School
Work done from P.V graph
A monatomic ideal gas expands from point A to point B along the path shown in the drawing which is shown at “click here”a) Determine the work done by the gas .
b) The temperature of the gas at point A is 154 K . What is its temperature at point B ?
c) How much heat has been added to the gas during the process ?
Physics Heat & Thermodynamics Level: High School
Work done in adiabatic expansion
Two moles of a monatomic ideal gas expand adiabatically, and its temperature decreases from 370 to 170 K .a) What is the work done by (or done to) the gas ? Including the algebraic sign .
b) What is the change in the internal energy of the gas ? Include the algebraic sign .
Physics Heat & Thermodynamics Level: High School
First Law of Thermodynamics
The pressure and volume of a gas are changed along a path ABCA in the figure which is shown at “click here” . The vertical divisions on the graph represent 3.00 x 10^5 Pa , and the horizontal divisions represent 5.00 x 10^-3 m^3 . Determine the work done (including algebraic sign) in each segment of the path .a) A to B
b) B to C
c) C to A
Physics Heat & Thermodynamics Level: High School
A gas , while expanding under isobaric conditions , does 420 J of work . The pressure of the gas is 1.6 x 10^5 Pa , and its initial volume is 1.60 x 10^-3 m^3 . What is the final volume of the gas ?
Physics Heat & Thermodynamics Level: High School
First Law of Thermodynamics
In exercising , a weight lifter loses 0.190 kg of water through evaporation , the heat required to evaporate the water coming from the weight lifter’s body . The work done in lifting weights is 1.45 x 10^5 Ja) Assuming that the latent heat of vaporization of perspiration is 2.42 x 10^6 J/kg , find the change in the internal energy of the weight lifter .
b) Determine the minimum number of nutritional calories of food (1 nutritional calorie = 4186 J ) that must be consumed to replace the loss of internal energy .
Physics Heat & Thermodynamics Level: High School
First Law of Thermodynamics
In moving out of a dormitory at the end of the semester , a student does 1.90 x 10^4 J of work , In the process , his internal energy decreases by 3.90 x 10^4 . Determine W,U , and Q (including the algebraic sign) .
Physics Modern Physics Level: High School
Radioactivity
How many radioactive atoms are present in a sample that has an activity of 0.5 microCi and a half-life of 10 years ? (1 curie = 3.7 x 1010 decays/ s )a) 9.5 x E22 atoms
b) 8.4 x E12 atoms
Physics Modern Physics Level: High School
Radioactivity
44 g of petrified wood was found in a petrified forest . A sample showed a 14 C activity of 100 decays / minute . How long has the tree been dead (in years) ? (The half-time of carbon -14 is 5730 years and freshly cut wood contains 6.5 x 1010 atoms of 14 C per gram) .a) 32,300
b) 15,600
c) 8,500
d) 4,700
e) 2,400
Physics Modern Physics Level: High School
Radioactivity
The half-life of 131-I is 8.04 days . Three days after it was prepared , its activity was 0.5 microCi, How many curies (in microCi) were initially prepared ?a) 8.60
b) 3.70
c) 0.65
d) 0.055
e) 0.0039
Physics Rotational Mechanics Level: High School
Rotaional Kinematics
A uniform solid cylinder which is shown at “click here” has a radius of 0.35 m and a mass of 25 kg . If these force were applied for 6.5 seconds find the angular velocity and angle that the cylinder has rotated through .
Physics Rotational Mechanics Level: High School
Rotational Kinematics
The angular momentum of a spinning wheel is 234 kg m^2/s . After application of a constant braking torque for 2.0 s , it slows and has a new angular momentum of 111 kg m^2/m. What is the torque applied ?
Physics Rotational Mechanics Level: High School
Rotational Kinematics
A spinning flywheel has rotational inertial I = 401.4 kg*m^2 . Its angular velocity decreases from 20.4 rad/s to zero in 274.2 s due to friction . What is the frictional torque acting ?