A resistor of unknown resistance and a 15-? resistor are connected across a 20-V emf in such a way that a 2.0 A current is observed in the emf. What is the value of the unknown resistance?
a.
75 ?
b.
12 ?
c.
7.5 ?
d.
30 ?
e.
5.0 ?
d
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A projectile is projected from the origin with a velocity of 20.0 m/s at an angle of 60.0 degrees above the horizontal. What is the maximum height of the projectile?
A. 8.40 m B. 9.50 m C. 10.9 m D. 15.3 m E. 20.2 m
To what do the terms node and antinode refer?
a) antinodes are points of no oscillation; nodes are points of maximum oscillation b) nodes are points of no oscillation; antinodes are points of maximum oscillation
A ray of light goes from one transparent material into another, as shown in the figure. What can you conclude about the indices of refraction of these two materials?
A) n1 ? n2 B) n1 > n2 C) n1 = n2 D) n2 ? n1 E) n2 > n1
A wheel having a moment of inertia of 5.00 kg ? m2 starts from rest and accelerates under a constant torque of 3.00 N ? m for 8.00 s. What is the wheel's rotational kinetic energy at the end of 8.00 s?
A) 57.6 J B) 64.0 J C) 78.8 J D) 122 J