In order for an object to experience a change in velocity, the object must experience which of the following? a) a net force
b) an acceleration
c) both of the above
d) none of the above

A15,000 kg rocket traveling at +230 m/s turns on its engines. over a 6.0 s period it burns 1,000 kg of fuel. an observer on the ground measures the velocity of the expelled gases to be −1,200 m/s.