What is the leading evidence for dark energy?
a. That the universe is expanding.
b. That dark matter is not affected by conventional energy.
c. That ordinary energy must have a complement.
d. That the rate of expansion of the universe is increasing.
e. The expansion of the universe is slowing down and could eventually reverse.
d
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Constant Acceleration Kinematics: A car is moving with a constant acceleration. At time t = 5.0 s its velocity is 8.0 m/s in the forward direction, and at time t = 8.0 s its velocity is 12.0 m/s forward. What is the distance traveled in that interval of time?
A. 10 m B. 20 m C. 30 m D. 40 m E. 50 m
Carnot Engine: One of the most efficient engines built so far has the following characteristics: The combustion chamber temperature is 1900°C, the exhaust temperature = 430°C, 7.0 × 109 cal of fuel produces 1.4 × 1010 J of work in one hour. (1 cal = 4.186 J)(a) What is the actual efficiency of this engine?(b) What is the power output of this engine?(c) What would be the maximum possible efficiency for an engine using the same temperature extremes?
What will be an ideal response?
Kirchhoff's Rules: For the circuit shown in the figure, R1 = 18 ?, R2 = 44 ?, R3 = 33 ?, R4 = 14 ?, R5 = 12 ?, V1 = 18 V, V2 = 12 V, and the batteries are ideal. Determine I1 and I2.
What will be an ideal response?
All of the following are true. Which of the following gives evidence that Earth's orbit is not perfectly circular?
A) The Sun's angular size changes throughout the year. B) Earth's seasons are not of exactly equal length. C) In North America, it is hotter in July than January. D) Both A and C E) Both A and B