Question1
A red train travelling at 63 km/h and a green train travelling at 140 km/h are headed toward one another along a straight, level track. When they are 910 m apart, each engineer sees the other's train and applies the brakes. The brakes slow each train at the rate of 1.0 m/s2.
(a) What is braking distance for the first train?
(b) What is braking distance for the second train?
(c) Is there any collision?
Question2
A potential difference of 98 mV exists between inner and outer surfaces of a cell membrane. The inner surface is negative relative to outer surface. How much work is required to eject a positive sodium ion (Na+) from the interior of the cell?