There is a 250-m-high cliff at Half Dome in Yosemite National Park in California. Suppose a boulder breaks loose from the top of this cliff. (a) How fast will it be going when it strikes the ground? (b) Assuming a reaction time of 0.300 s, how long will a tourist at the bottom have to get out of the way after hearing the sound of the rock breaking loose (neglecting the height of the tourist, which would become negligible anyway if hit)? The speed of sound is 335 m/s on this day.
There is a 250-m-high cliff at Half Dome in Yosemite National Park in California. Suppose a boulder breaks loose from the top of this cliff. (a) How fast will it be going when it strikes the ground? (b) Assuming a reaction time of 0.300 s, how long will a tourist at the bottom have to get out of the way after hearing the sound of the rock breaking loose (neglecting the height of the tourist, which would become negligible anyway if hit)? The speed of sound is 335 m/s on this day.
There is a 250-m-high cliff at Half Dome in Yosemite National Park in California. Suppose a boulder breaks loose from the top of this cliff. (a) How fast will it be going when it strikes the ground? (b) Assuming a reaction time of 0.300 s, how long will a tourist at the bottom have to get out of the way after hearing the sound of the rock breaking loose (neglecting the height of the tourist, which would become negligible anyway if hit)? The speed of sound is 335 m/s on this day.
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Nature of Resistance
Temperature-Resistance Relationship
Ohm's Law, Energy and Power
Kirchhoff's Law
• Maxwell's Mesh Analysis
1. A coil of copper wire (p = 10.37 2-cmil/ft) has a length of 600 ft. What is the length of an aluminum conductor
(p 17 cmil/ft), if its cross-sectional area and resistance are the same as those of the copper coil? (Hint: Look
for conversion of inches to mils and square inches to square foot. Include it in your solution.) (1 pt)
2. The copper field winding of an electric machine has a resistance of 46 at temperature of 22°C. What will be
its resistance at 75°C? (Use do = 0.00427 /°C for copper) (1 pt)
3. The resistivity of a copper rod 50 ft long and 0.25 inch in diameter is 1.76 μ at 20°C. What is its resistance at -
20°C? (1 pt)
4. When two resistors A and B are connected in series, the total resistance is 36 2. When connected in parallel, the
total resistance is 8 Q. What is the ratio of the resistance RA to resistance RB? Assume RA < RB. (1 pt)
5. The…
2. Two equally strong individuals, wearing
exactly the same shoes decide to do a tug of
war. The only difference is individual A is
2.5 meters tall and individual B is 1.5 meter
tall. Who is more likely to win the tug of
war?
6. A car drives at steady speed around a perfectly
circular track.
(a) The car's acceleration is zero.
(b) The net force on the car is zero.
(c) Both the acceleration and net force on the car
point outward.
(d) Both the acceleration and net force on the car
point inward.
(e) If there is no friction, the acceleration is
outward.
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