I NEED HELP ASAP In which situation is the speed of the car constant while its velocity is changing?

The car travels down a straight track at 30 m/sec

The car travels around a circular track at 30 m/s

The car begins from rest and accelerates to 20 m/s

The car begins traveling at 30 m/s and decreases to 15 m/s

Ajournal bearing has a journal diameter of 3.250 in with a unilateral tolerance of 20.003 in. the bushing bore has a diameter of 3.256 in and a unilateral tolerance of 0.004 in. the bushing is 2.8 in long and supports a 700-lbf load. the journal speed is 900 rev/min. find the minimum oil film thickness and the maximum film pressure for both sae 20 and sae 20w-30 lubricants, for the tightest assembly if the operating film temperature is 160°f. a computer code is appropriate for solving this problem.