The train's machinist was told that there was an obstacle on the tracks and he would stop before reaching it. when
starts braking, machinist looks the speed radar and reads the speed 144 km/h. deceleration is uniform and the train
stopped ahead the obstacle after 60 seconds.
calculate the train's acceleration in those 60 seconds.
at what distance from train was the obstacle?

The atoms in a nickel crystal vibrate as harmonic oscillators with an angular frequency of 2.3 × 1013 rad/s. the mass of a nickel atom is 9.75 × 10-26 kg. what is the difference in energy between adjacent vibrational energy levels of nickel? (h = 6.626 × 10-34 j • s, , 1 ev = 1.60 × 10-19 j)

Which type of energy would have nothing to do with ironing clothes? a. heat b. chemical c. electrical d. mechanical

Oxygen gas enters well-insulated diffuser at 25 lbf/in.2, 420r, with a velocity of 860 ft/s through a flow area of 1.6 in.^2. at the exit, the flow area is 12 times the inlet area, and the velocity is 19 ft/s. the potential energy change from inlet to exit is negligible. assuming ideal gas behavior for the oxygen and steady-state operation of the diffuser, determine the following: (a) the exit temperature, in r(b) the exit pressure, in lbf/in.^2 (c) the mass flow rate, in lb/s