Two carts collide on a level, friction-less track. cart a has a mass of 200 g and is initially stationary. cart b has a mass of 100 g and is initially moving with a velocity of +2.0 m/s. after the collision between the carts, cart b has a velocity of -0.5 m/s.
calculate the velocity of cart a after the collision.
(use conservation of momentum, ke is not conserved.)

In a closed system, the total energy prior to an energy transformation is the total energy after. a. equal to b. unrelated to c. greater than d. less than

Agroup of students is studying convection currents. they fill two identical balloons with the same amount of helium. one balloon is placed in a freezer and the other in an area with warm air. after 10 minutes, the balloons are released from a height of 1 meter. which of the following do the students most likely observe? question 2 options: the balloons rise at the same rate. both balloons are the same size. the ballons both rise. the cold ballon is larger than the warm balloon. the cold balloon expands and rises. the warm balloon shrinks and sinks. the warm balloon expands and rises. the cold balloon shrinks and sinks.

Which is the correct symbol for an isotope of iodine with 53 protons and 78 neutrons?