Which evidence best supports that a device is an electric motor? A. Electricity flows when a coil of wire is rotated by a hand crank.
B. Electricity flows from a battery through a loop of wire which then causes a needle to move.
C. Electricity flows from a battery to loop of wire and then through a galvanometer back to the battery.
D. Electricity flows through a coil of wire that is rotating because a magnet is pushing on the coil of wire.

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.