An engineering student was helping in the design of a new runway. His mentor told him the airplanes must reach a ground velocity of 55 m/s before they can take off. These planes are
capable of being accelerated at a rate of 2.8 m/s?.
a. How long will it take the planes to reach takeoff speed?
b. What must be the minimum length of the runway?

An ambulance emits a frequency of 450 hz from its siren. what frequency is heard by a man as the ambulance moves toward him? less than 450 hz more than 450 hz 450 hz 0 hz

Look at the potential energy diagram for a chemical reaction. which statement correctly describes the energy changes that occur in the forward reaction?

Red light strikes a metal surface and electrons are ejected. if violet light is now used with a 10% greater intensity, what will happen to the ejection rate (number of ejected electrons per second) and the maximum energy of the electrons? a) greater ejection rate; same maximum energyb) same ejection rate; greater maximum energyc) greater ejection rate; greater maximum energyd) same ejection rate; same maximum energye) none of the above answers are correct