Questions asked by boobookitty

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• A 2000-kg car is moving at 10 m/s. (1) What is the car kinetic energy? (2) What is the car linear momentum? 
  
• A lifter takes 5 s to lift a 20-kg object by 10 m high. (1) What is the work done against gravity? (2) What is the power of the lifter?   
  
• Find the heat required for 5-kg water to be heated from 30 Celsius degree to 50 Celsius degree. Can you express the temperature of 50 Celsius degree in Fahrenheit scale?
  
• A sphere with radius of 2 m is entirely immersed in water. (1) what is the buoyant force on the sphere by water? (2) what is the buoyant force by the air?(Given water and air densities to be is 1000 kg/m3 and 1.3 kg/m3, respectively)  
  
• A 20-kg boy runs at 4 m/s  and jumps on a rest 5-kg skateboard. (1) Find the skating velocity. (2) Which law do you apply to solve this problem?   
  
• 1: For a given amount, type, and temperature of gas, when its pressure is increased from 200 kPa to 500 kPa, what will its volume be if its initial volume is 3 cubic meters?
  
• After a system is added 40-J heat, the system does 30-J work. How do you find the change of the system’s internal energy?
  
• What is the electric force between two charges of 5 nC and 20 nC when the distance between them is 10 cm?
  
• A transformer has 150 turns in the primary coil and 20 turns in the secondary coil. When a 120-V potential difference is applied to the primary coil, what is the potential difference in the secondary coil?
  
• If 360 ocean water waves, each 20 meters long, hit the shore every hour, what is the wave speed? What is the wave period?
  
• Light speed in a medium is measured as 2×108 m/s. What if the index of refraction for the medium? What is the apparent depth of a fish with real depth of 9 meters in the medium?
  
• Find the Coulomb force between two electric charges of #4 xx 10^(-6)# #C# and #5 xx 10^(-6)# #C#, if the distance between the two charges is #2# #cm#?
  
• When a 120 V potential difference is applied across a 30 Ω resistance of electric device. What is the current through the electric device? What is the power of the electric device?
  
• A transformer has 100 turns in the primary coil and 25 turns in the secondary coil. When a 120 V potential difference is applied to the primary coil, what is the potential difference in the secondary coil?
  
• 10 ocean water waves whose crests are 12 meters apart reach or hit the shore each minute. What is the wavelength, wave frequency, and wave speed?
  
• The rate at which electric charge flow through?
  
• The half-life of a certain radioactive isotope is 6 hours. If we start out with 100 grams of the isotope, how many grams will be left after 1 day?
  
• Find the binding energy of , whose atomic mass is 12.019 u?
  
• Find the de Broglie wavelength of a particle with mass of 6.4×10-27 kg and velocity of 2×108 m/s?