A 150-kg crate is placed on an adjustable inclined plane. If the crate slides down the incline with an acceleration of 0.70 m/s2 when the incline angle is 20°, then what should the incline angle be for the crate to slide down the plane at constant speed? (g = 9.8 m/s2)
a. 21°
b. 16°
c. 11°
d. 26°
e. 6°
b
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The resolving power of a telescope is ____
a. a measure of the minimum angular separation that can be seen with the telescope. b. a measure of the maximum angular separation that can be seen with the telescope. c. a measure of the amount of light that the telescope can gather in one second. d. the separation between the objective and the image. e. a measure of how blurry object appear in the telescope.
Interstellar gas clouds may collapse to form stars if they
a. have very high temperatures. b. encounter a shock wave. c. rotate rapidly. d. are located near main sequence spectral type K and M stars. e. All of the other choices are correct.
In an elastic collision between two bodies of mass m1 and m2, with m2 initially at rest, mass 1 moves off at angle ? relative to the direction of its initial velocity and mass 2 at angle ?. An exam paper shows the equations below: m1v1i0 = m1v1f cos? + m2v2f sin?= m1v1f sin? + m2v2f cos?What error(s) has the student made?
A. In the first equation, m2v2f sin? should be m2v2f cos?. B. In the second equation, m2v2f cos? should be m2v2f sin?. C. In the second equation, the plus sign between the terms on the right should be a minus sign. D. All of the errors listed above. E. Only errors (a) and (b) above.
What is the kinetic energy of a 0.160-kg ball thrown at 40.0 m/s (90.0 mph)?
a. 54.0 J b. 64.0 J c. 108 J d. 128 J e.newton-meter.