There is a parlor trick in which person#1 hangs a dollar bill from their hand so that it dangles between the fingers of person#2. person#1 releases the bill, and person#2 must try to close their fingers in time to catch the bill before it falls completely through their fingers. the length of the bill is 15.6 cm and a typical person's reaction time is 0.20 seconds. the typical person will not be able to catch the bill. calculate how fast a person's reaction time would have to be to just barely catch the falling bill (assume that you can neglect air friction).

Jake has a nine month old son. how can he build his self esteem

Scientists use laser range-finding to measure the distance to the moon with great accuracy. a brief laser pulse is fired at the moon, then the time interval is measured until the "echo" is seen by a telescope. a laser beam spreads out as it travels because it diffracts through a circular exit as it leaves the laser. in order for the reflected light to be bright enough to detect, the laser spot on the moon must be no more than 1.0 km in diameter. staying within this diameter is accomplished by using a special large-diameter laser. part a if λ = 540nm , what is the minimum diameter of the circular opening from which the laser beam emerges? the earth-moon distance is 384,000 km. express your answer to two significant figures and include the appropriate units.

For the car in the picture ,in which direction is the normal force? -into the screen -down -out of the screen -up