UNIT Sample readings
Use your own results if possible, but if not make use of these
sample readings
Mass of water being heated = 100 g
Starting temperature of cold water = 22°C
Steady current I through heater = 1.5 A
Steady p. d. V across heater = 12.0V
Total time t of heating = 10 min = 600 s
Final temperature of warm water = 47°C

Analysing the readings

1. What is the power of the heater (in watts)?
2. How many joules of heat energy did the heater supply in total?
3. Through how many degrees C did this energy warm the
100 g of water?
4. How much energy, therefore, was needed to warm 1 kg of
water by 1°C?

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A2k pendulum has a speed of 1 m/s at a height of 1/2 meter

Awater slide of length l has a vertical drop of h. abby's mass is m. an average friction force of magnitude f opposes her motion. she starts down the slide at initial speed vi. use work-energy ideas to develop an expression for her speed at the bottom of the slide. then evaluate your result using unit analysis and limiting case analysis. express your answer in terms of the variables h, m, l, vi, f and appropriate constants. vf v f

Two loudspeakers, 5.5 m apart and facing each other, play identical sounds of the same frequency. you stand halfway between them, where there is a maximum of sound intensity. moving from this point toward one of the speakers, you encounter a minimum of sound intensity when you have moved 0.33 m . assume the speed of sound is 340 m/s.part a) what is the frequency of the sound? part b) if the frequency is then increased while you remain 0.21 m from the center, what is the first frequency for which that location will be a maximum of sound intensity? express your answer to two significant figures and include the appropriate units.