Some consumer groups urge pregnant women not to use electric blankets, in case there is a health risk from the magnetic fields from the approximately 1 A current in the heater wires. a. Estimate, stating any assumptions you make, the magnetic field strength a fetus might experience. What percentage of the earth’s magnetic field is this? b. It is becoming standard practice to make electric blankets with minimal external magnetic field. Each wire is paired with another wire that carries current in the opposite direction. How does this reduce the external magnetic field?
Some consumer groups urge pregnant women not to use electric blankets, in case there is a health risk from the magnetic fields from the approximately 1 A current in the heater wires. a. Estimate, stating any assumptions you make, the magnetic field strength a fetus might experience. What percentage of the earth’s magnetic field is this? b. It is becoming standard practice to make electric blankets with minimal external magnetic field. Each wire is paired with another wire that carries current in the opposite direction. How does this reduce the external magnetic field?
Some consumer groups urge pregnant women not to use electric blankets, in case there is a health risk from the magnetic fields from the approximately 1 A current in the heater wires.
a. Estimate, stating any assumptions you make, the magnetic field strength a fetus might experience. What percentage of the earth’s magnetic field is this?
b. It is becoming standard practice to make electric blankets with minimal external magnetic field. Each wire is paired with another wire that carries current in the opposite direction. How does this reduce the external magnetic field?
What is the current, in amps, across a conductor that has a resistance of10 Ω and a voltage of 20 V?
2. A conductor draws a current of 100 A and a resistance of 5 Ω. What is thevoltageacross the conductor?
3. What is the resistance, in ohm’s, of a conductor that has a voltage of 80 kVand acurrent of 200 mA?
4. An x-ray imaging system that draws a current of 90 A is supplied with 220V. What is the power consumed?
5. An x-ray is produced using 800 mA and 100 kV. What is the powerconsumed in kilowatts?
Part C
Find the height yi
from which the rock was launched.
Express your answer in meters to three significant figures.
Learning Goal:
To practice Problem-Solving Strategy 4.1 for projectile motion problems.
A rock thrown with speed 12.0 m/s and launch angle 30.0 ∘ (above the horizontal) travels a horizontal distance of d = 19.0 m before hitting the ground. From what height was the rock thrown? Use the value g = 9.800 m/s2 for the free-fall acceleration.
PROBLEM-SOLVING STRATEGY 4.1 Projectile motion problems
MODEL: Is it reasonable to ignore air resistance? If so, use the projectile motion model.
VISUALIZE: Establish a coordinate system with the x-axis horizontal and the y-axis vertical. Define symbols and identify what the problem is trying to find. For a launch at angle θ, the initial velocity components are vix=v0cosθ and viy=v0sinθ.
SOLVE: The acceleration is known: ax=0 and ay=−g. Thus, the problem becomes one of…
Chapter 24 Solutions
College Physics: A Strategic Approach (3rd Edition)
Fundamentals of Anatomy & Physiology (11th Edition)
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