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?

Apendulum has a mass of 1.5 kg and starts at a height of 0.4 m. if it is released from rest, how fast is it going when it reaches the lowest point of its path? acceleration due to gravity is g = 9.8 m/s2. a. 2.8 m/s b. 0 m/s c. 5.9 m/s d. 4.3 m/s

Smallest intensity of a stimulus that you can detect 50 percent of the time is

Materials will have different energies associated with the electrons inside them. this is related to how strongly bound they are by their work function. if we sandwich a material with a very low energy between two materials with a high energy, we create a trap for an electron. if this trap is very narrow in one direction in comparison to the others, this is approximately a 1-dimensional box that confines the electron. what is the lowest energy of an electron in the box if the thinnest direction across the materials is 4.81 nm?