A rollercoaster was moving from point A to B, and then to C, with the instantaneous velocity 5m/s, 15m/s, and 10m/s, respectively. The instaneous velocity at a point between B and C could be
A)
less than 5m/s.
B)
less than 10m/s.
greater than 10m/s.
D)
greater than 15m/s.

Africtionless piston-cylinder contains 50 l of saturated liquid r-134a. the piston has a mass and an area resulting in an applied pressure of 500 kpa on the refrigerant. the refrigerant is now heated until its temperature rises to 70∘c. calculate the work (in kj) done during this process.