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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a solenoid is created by wrapping a l = 90 m long wire around a hollow tube of diameter d = 4.5 cm.   the wire diameter is d = 0.9 mm.   the solenoid wire is then connected to a power supply so that a current of i = 9 a flows through the wire.

randomized variablesl = 90 m

d = 4.5 cm

d = 0.9 mm

i = 9 a                                          

write an expression for the number of turns, n, in the solenoid. you do not need to take into account the diameter of the wire in this calculation.

calculate the number of turns, n, in the solenoid.

write an expression for the length of the solenoid (l2) in terms of the diameter of the hollow tube d.

calculate the length of the solenoid (l2)   in meters.

calculate the magnitude of the magnetic field at the center of the solenoid in teslas.

explanation:

think its the third option

force is mass*acceleration.

we have a very small mass: 11.4*0.001 kg

if we want 0.035n of force, we need an acceleration:

0.035 = 11.4*0.001*a

a = 0.035/(11.4*0.001) m/s^2

it has to be b, about 97 percent.