If the displacement of an object is given in SI units by Dx = -5t + t 2, at t = 2 s its velocity and acceleration are, respectively: (Hint: Use dimensional analysis along with the equations for motion with constant acceleration.)
a. positive, positive.
c. negative, negative.
b. positive, negative.
d. negative, positive.
D
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Why is Venus's atmosphere hotter than Mercury even though it is farther from the Sun?
a. Venus has a thin atmosphere thus allowing more of Sun's radiation to enter. b. Venus contains water vapor in its atmosphere, which absorbs more heat. c. Venus contains 96 percent CO2 resulting in very hot temperatures d. Mars contains more CO2, which has a cooling effect on its atmosphere. e. Mercury has a hotter atmosphere because it is closer to the Sun than Venus.
The gas in the interstellar medium consists of mostly heavy elements
Indicate whether the statement is true or false
A string is wrapped tightly around a fixed pulley that has a moment of inertia of 0.0352 kg ? m2 and a radius of 12.5 cm. An object of mass of 423 g is attached to the free end of the string
With the string vertical and taut, the object is gently released so it can descend doe to the gravitational force exerted on it by Earth. As the object descends, the string unwinds and causes the pulley to rotate, but does not slip on the pulley. What is the speed of the object after it has fallen through 1.25 m? A) 2.00 m/s B) 2.28 m/s C) 1.97 m/s D) 3.94 m/s E) 4.95 m/s
Equal currents of magnitude I travel into the page in wires M and N. Eight directions are indicated by letters A through H
The direction of the magnetic field at point P is
a.
B.
b.
C.
c.
D.
d.
E.
e.
F.