What frequency will you hear if a truck is driving toward you at 20 m/s sounding a horn of frequency 300 hz. assume the speed of sound to be 340 m/s.

=319Hz

Explanation:

This question is on sound waves

General formulae;

Frequency of observer= f of source*[ (v of sound+ v of observer)/(v of sound-v of source)]

where f is frequency and v is velocity

Given;

Velocity of sound = 340m/s

frequency of source = 300 Hz

Velocity of observer=0m/s

Velocity of source/truck= 20m/s

Substitute values in the formulae;

Frequency of observer= 300× {(340+0)/(340-20)}

                                       =300×{ 340/320}

                                       =300×340/320

                                       =318.75

                                       =319Hz

given data:

determine the horse power (h.p) = ?

force applied to move the box(f) = 10 pounds,

box lifted from a distance         (d) = 3 feet

time taken to lift                         (t) = 10 sec,

the horse power is defined as amount of work required to move a load. the horse power is equal to 550 foot-pound per second

                  1 h.p   = 550 foot-pound/second

it can also be defined as the the load that need to be move a body for certain distance in a certain amount of time.

mathematically,

                      h.p = (force × distance)/ time

                            = (10 × 3)/ 10

                            = 30/10

                            = 3 foot -pound/sec

hence, the horse power is needed to move the box is 3 foot-pound/second

important note: 1 h.p = 550 foot-pound/second = 746 watts

the temperature in kelvin of 2.0 dm3 of an ideal gas is doubled and its pressure is increased by a factor of four. what is the final volume of the gas