Physics Force & Laws Of Motion Level: High School
Circular Motion
An 85 kg Tarzan plans to cross a gorge by swinging on a 4-meter long vine . If the vine can hold no more than 1.50 x 10^3 N , what is the maximum velocity Tarzan can have when swimming across the gorge ?
Physics Force & Laws Of Motion Level: High School
Circular Motion
A racecar of mass equal to 1.20 x 10^3 kg travels around a circular racetrack that has a radius of 75.0 meters . The car moves around the track at 5 revolutions every 200.0 sec .a) Calculate the frictional force necessary to keep the car moving in its circular path ?
b) If the velocity of the car is traveling at the maximum it can have without skidding, what is the coefficient of friction between the track and car’s tires ?
Physics Rotational Mechanics Level: High School
In 1990 , a pizza of a radius 18.7 M was baked in South Africa , Suppose this placed on a rotating platform . If the pizza accelerated from rest to an angular velocity of 125 rad/sec in 25.0 s, what is the angular displacement of a point on the edge of the pizza during this time ?
Physics Measurements Level: High School
A particular bird’s eye can just distinguish objects that subtend (opposite to ) an angle no smaller than about 3.0 x 10^-4 radians .a) How many degrees is this ?
b) How small an object can the bird distinguish when flying at a height of 100.0 meters ?
Physics Gravitation Level: High School
Space station beta is positioned 12.8 x 10^6 M above the earth’s surface .a) What is the value of “g” , the acceleration due to gravity , inside the station ?
b) What would a 60.0-kg person weigh on board station beta ?
Physics Modern Physics Level: High School
Photoelectric Effect
The photoelectric effect is important for two reasons , firstly , it provides strong evidence for the particle nature of light , and secondly , it has a large number of practical applications .a) Give one experimental observation coming from the study of the photoelectric effect that provides strong support for the particle theory of light .
b) State two practical applications of the photoelectric effect .
c) The work function of sodium is 2.46 eV .
i) Find the maximum frequency of radiation needed to eject photoelectrons from a sodium surface .
ii) If the sodium , surface is illuminated with radiation of wavelength 3.00 x 10^-7 metres , calculate the maximum kinetic energy of ejected photoelectrons .
Physics Electromagnetic Waves Level: High School
Light is an example of an electromagnetic wave .a) Why is it called electromagnetic ?
b) If the light wave were generated at a frequency of 5.6 x 10^14 Hz , what would be its wavelength ?
c) If a polarizer is placed in front of the beam of light what would happen ? Explain why this occurs .
d) Radiation of light can be determined by the Stephen-Bolzmann equation .
i) What does this equation predict will happen if the temperature of the light source is increased ?
ii) In what units would delta Q / delta t be expressed ?
iii) What does the symbol e represent in this equation ?
Physics Magnetism,Magnetic Effects Of Current Level: High School
Moving Coil Galvanometer
The diagram above shows the basic structure of a moving-coil galvanometer . The moving coil , ABCD , can pivot freely about a vertical axis shown by the dotted line . AB = 0.8 cm and BC = 1.2 cm . A current is flowing in a clockwise direction through the coil .a) What is the direction of the magnetic field between the poles of the field magnets ?
i) left ii) right iii) toward observer iv) away from observer
b) What is the direction of the force acting on the side BC of the coil ?
i) left ii) right iii) toward observer iv) away from observer
c) If the magnitude of the force exerted on the side BC of the coil is 2 x 10^-6 N , calculate the magnitude of the net torque on the coil .
d) To be used as an ammeter , a shunt resistor would have to be connected in parallel with the galvanometer , Explain why ?
Physics Current Electricity Level: High School
Resistance
A 6.0 volt battery is connected in parallel with two identical lamps , each having a resistance of 24 ohms , Under these conditions , the resistance of the battery is negligible .a) Calculate the total resistance of the lamps ?
b) Calculate the current flowing through each lamp ?
c) Calculate the power consumption of each lamp .
d) What would happen to the current drawn from the battery if one of the lamps burnt out ?
e) Would it be hazardous if you stuck your finger in one of the lamp socket with the battery connected ? Why ?
Physics Current Electricity Level: High School
Resistance
a) Why are metals good conductors of electricity ?
b) What properties of a conductor would determine its electric resistance ?
c) Why does the resistance of a metallic conductor increase at higher temperature ?
Physics Electrostatics Level: High School
Capacitor
A capacitor consists of two large parallel charged plates separated by an insulating material , as shown at “click here”.a) What name is given to the insulating material in a capacitor ?
b) In what units would the capacitance of the capacitor be expressed ?
c) What is the basic function of a capacitor ?
d) Use a diagram to show the nature of the electric field between the plates .
e) Would moving the plates of the capacitor further apart increase , decrease or have no effect on its capacitance ?
Physics Electrostatics Level: High School
The operation of a fluorescent light tube involves the transfer of positive mercury ions along the tube under the action of an electric field . At a point P in a fluorescent tube 1.2 meters long , the electric field is 25 NC-1 south , and a positive mercury ion at point P is acted on by a force of 8.0 x 10^-18 N .a) What is the direction of the force acting on the mercury ion ?
b) Calculate the charge on the ion
c) What minimum potential difference must exist between the ends of the tube in order to produce the field of 25 NC^-1 ?
Physics Heat & Thermodynamics Level: High School
The chemical reaction below shows the conversion of 3 moles of ethyne to 1 mole of benzene .a) If the standard free energies of formation for ethyne and benzenerare 209 kJ mol-1 and 130 kJ mol-1 , respectively, determine by calculation whether this reaction is theoretically possible under standard conditions .
b) If it were possible for this reaction to occur , would the change in enthalpy (delta H) be greater than ,less than or the same as the change in internal energy (delta U) ?
c) Would the change in entropy for the reaction be positive ,negative or zero ?
Physics Heat & Thermodynamics Level: High School
Heat Engine
a) Redraw the diagram which is shown at “click here” for the heat engine , and label the direction in which QH , QL and W are transferred .
b)What relationship would exist between QH, QL and W ?
c) While this engine operates on a Carnote cycle , it absorbs 440 of heat from the high temperature reservoir at 227 degree C , and it loses 330 J of heat to the low temperature reservoir .
(i) What is the value o TL ?
(ii) Calculate the efficiency of the engine .
d) If it were possible to have the low temperature reservoir at absolute zero , would the efficiency of the engine be 100 % ?
Physics Force & Laws Of Motion Level: High School
Newton’s Second Law
Two blocks , masses m1 and m2 , are connected by a massless cord (see the figure at “click here”) . If the two blocks are accelerated uniformly on a frictionless surface by applying a force of magnitude T2 to a second cord connected to m2 , what is the ratio of the tensions in the two cord in the terms of the masses ? T1/T2 = ?