What effect do even thin clouds of dust have on light passing through them?
A) The light that passes through them is blue shifted due to the cloud's approach.
B) It dims and reddens the light of all more distant stars.
C) Even a little can completely block all light, such as the Horsehead Nebula.
D) Its motion causes the light of stars beyond to twinkle.
E) Its motion causes all light to be redshifted as it passes through these clouds.
B
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A uniform rod has a weight of 40. N and a length of 1.0 m. It is hinged to a wall (at the left end), and held in a horizontal position by a vertical massless string (at the right end), as shown in Fig. 8-7
What is the magnitude of the torque exerted by the string about a horizontal axis which passes through the hinge and is perpendicular to the rod? A) 40 m ? N B) 10 m ? N C) 5.0 m ? N D) 20 m ? N E) 30 m ? N
_______ Force is the force that keeps an object moving on a curved path that is directed inward towards the center of a rotation.
Fill in the blank(s) with correct word
A doubly charged ion with speed 6.9 × 106 m/s enters a uniform 0.80-T magnetic field, traveling perpendicular to the field. Once in the field, it moves in a circular arc of radius 30 cm. What is the mass of this ion? (e = 1.60 × 10-19 C)
A) 11 × 10-27 kg B) 6.7 × 10-27 kg C) 3.3 × 10-27 kg D) 8.2 × 10-27 kg
A 30-kg child rides on a circus Ferris wheel that takes her around a vertical circular path with a radius of 20 m every 22 s. What is the magnitude of the resultant force on the child at the highest point on this trajectory?
a. 49 N b. 0.29 kN c. 0.34 kN d. 0.25 kN e. 0.76 kN