A train that is powered by magnetism and electricity is currently being tested in Japan. A student wants to build a model of this train. Which test will best determine if the model train works? A attach the model train to an electric fan B connect the model train to a solar panel C attach the model train to a bottle rocket connect the model train to an electromagnet​

Which of the following changes will result in a stronger electromagnet? a. using fewer coils of wire b. using a higher voltage c. using a shorter nail d. using a longer wire

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.

Explain what it means to view something from a frame of reference. provide an example that illustrates your explanation. (4 points)