Consider a → in the positive direction of x , b → in the positive direction of y , and a scalar d. What is the direction of b → /d if d is (a) positive and (b) negative? What is the magnitude of (c) a → · b → and (d) a → · b → /d ? What is the direction of the vector resulting from (e) a → × b → and (f) b → × a → ? (g) What is the magnitude of the vector product in (e)? (h) What is the magnitude of the vector product in (f)? What are (i) the magnitude and (j) the direction of a → × b → /d if d is positive?
Consider a → in the positive direction of x , b → in the positive direction of y , and a scalar d. What is the direction of b → /d if d is (a) positive and (b) negative? What is the magnitude of (c) a → · b → and (d) a → · b → /d ? What is the direction of the vector resulting from (e) a → × b → and (f) b → × a → ? (g) What is the magnitude of the vector product in (e)? (h) What is the magnitude of the vector product in (f)? What are (i) the magnitude and (j) the direction of a → × b → /d if d is positive?
Consider
a
→
in the positive direction of x
,
b
→
in the positive direction of y, and a scalar d. What is the direction of
b
→
/d if d is (a) positive and (b) negative? What is the magnitude of (c)
a
→
·
b
→
and (d)
a
→
·
b
→
/d? What is the direction of the vector resulting from (e)
a
→
×
b
→
and (f)
b
→
×
a
→
? (g) What is the magnitude of the vector product in (e)? (h) What is the magnitude of the vector product in (f)? What are (i) the magnitude and (j) the direction of
a
→
×
b
→
/d if d is positive?
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…
Human Physiology: An Integrated Approach (8th Edition)
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