Two airplanes flying 1.0 km apart at the same altitude spot a target ahead of them on the ground. the angles of depression subtended by the target at the two airplanes are 45o and 37o. the airplanes and the target are in the same vertical plane. what is the altitude (in meters) at which the planes are flying? (note: for the distances involved, the earth can be considered as flat.)
a. 2900
b. 3060
c. 1000
d. 2000

Air is held within a frictionless piston-cylinder container, which is oriented vertically. the mass of the piston is 0.45 kg and the cross-sectional area is 0.0030 m2. initially (state 1) the pressure of the gas is sufficient to support the weight of the piston as well as the force exerted by the atmospheric pressure ( 101.32 kpa). the volume occupied by the air within the cylinder in state 1 is 1.00 liter. one end of a spring (with spring constant k = 1000 n/m) is attached to the top of the piston, while the other end of the spring is attached to a stage that can move vertically. initially the spring is undeflected and therefore exerts no force. then the stage is then moved quasistatically downward a distance of 10.0 cm, at which point the system reaches state 2. the piston-cylinder is not insulated; rather it remains in diathermal contact with the surroundings, which are at a constant temperature of 300 k. what is the change of pressure within the container?

Jessie ran 5000 meters from the cops and an average speed of 6 meters / second before he got caught . how long did he run?

Exercise 2. find the wavelength of a photon emitted when an electron jumps from the n = 3 energy level down to the n = 2 energy level. where is this photon in the electromagnetic spectrum?