At a given instant, the acceleration of a certain particle is zero. This means that
A) the velocity is constant.
B) the velocity is increasing.
C) the velocity is decreasing.
D) the velocity is not changing at that instant.
E) the velocity is zero.
D
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What is Newton's Second law of motion?
A. Force equals mass times acceleration, F = ma. B. When two bodies interact, they create equal and opposite forces on each other. C. Every mass exerts a force on any other mass that is proportional to the product of the masses divided by the square of the distance between them. D. A body continues in a state of rest or uniform motion in a straight line unless made to change that state by forces acting on it.
A future news release might report that a new planet has been found around a star very similar to our Sun. The system contains other planets as well like our solar system. This newly discovered planet is claimed to have a mass 40 times that of Earth and is located nearly 25 AU from the star it orbits. Which of the following would be a reasonable prediction about this planet, assuming it formed
like our solar system? I. The planet will probably have a mean density of around 5 g/cm3. II. The planet will probably have a radius of around five to ten times greater than Earth's. III. The planet will probably have several satellites. IV. The planet will probably have a composition that is mostly hydrogen and helium. a. I & IV b. I, II, & III c. II, III, & IV d. I, II, & IV e. I, II, III, & IV
The point in Earth's orbit where Earth is farthest from the sun is known as
a. aphelion. b. perihelion. c. precession. d. the winter solstice e. a and d
An airplane flies 160 km at a constant altitude in a direction 30.0° north of east. A wind is blowing that results in a net horizontal force on the plane due to the air of 2.40 kN in a direction 10.0° south of west
How much work is done by the air on the plane? A) -3.61 × 108 J B) -1.31 × 108 J C) -2.94 × 108 J D) 2.94 × 108 J E) 1.15 × 108 J