That's because helium molecules are not packed together as densely as air molecules are. It is this simple reason that helium balloons float in the air.

1) sections 1, 2, and 10 are significant primarily because they suggest the likelihood that a) widow wycherly is actually the woman in the full-length portrait. b) dr. heidegger wants to include his guests in an experiment with the water. c) dr. heidegger plans to drink some of the water from the vase and needs witnesses. d) the guests will be asked to witness dr. heidegger's transformation when he drinks the water.

If the chemical properties of a substance remain unchanged and appearance or shape of a substance changes it is called a ?

Astudent throws a water balloon with speed v0 from a height h = 1.76 m at an angle θ = 21° above the horizontal toward a target on the ground. the target is located a horizontal distance d = 9.5 m from the student’s feet. assume that the balloon moves without air resistance. use a cartesian coordinate system with the origin at the balloon's initial position. (a) what is the position vector, rtarge t, that originates from the balloon's original position and terminates at the target? put this in terms of h and d, and represent it as a vector using i and j. (b) in terms of the variables in the problem, determine the time, t, after the launch it takes the balloon to reach the target. your answer should not include h. (c) create an expression for the balloon's vertical position as a function of time, y(t), in terms of t, vo, g, and θ. (d) determine the magnitude of the balloon's initial velocity, v0, in meters per second, by eliminating t from the previous two expressions.