In a new experiment, a spring is attached to the right end of cart A. Cart B is at rest between the photogates when cart A is given an initial speed to the right, passes through photogate X, and collides with cart B. The speed of each cart before and after the collision is measured. It is discovered that the sum of the kinetic energies of the two carts after the collision is about 5% greater than the kinetic energy of cart A before the collision. Which of the following is the best explanation for the difference in the kinetic energy
a. The scale used to determine the masses of the carts is off by 5%
b. During the collision, some of the kinetic energy of the carts is converted to heat.
c. Some of the elastic potential energy of the spring Is converted to kinetic envoy
d. There is a small amount of friction between the track and the sous
e. One end of the track is slightly higher than the other

Ms.hidalgo opens the door to her classroom. her classroom is 60 degrees and the air outside is 80. predict what will happen using your knowledge of how heat flows.

Explain why electric current cannot exist if a current doesn't have a voltage source.

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.