The Starship Enterprise returns from warp drive to ordinary space with a forward speed of 51 km/s . To the crew's great surprise, a Klingon ship is 110 km directly ahead, traveling in the same direction at a mere 30 km/s. Without evasive action, the Enterprise will overtake and collide with the Klingons in just about 5.2 s. The Enterprise's computers react instantly to brake the ship. What magnitude acceleration does the enterprise need to just barely avoid a collision with the klingon ship? Assume the acceleration is constant.

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.