an engine is approaching a hill at a constant speed when it is at a distance of 0 9km, - Science - Sound

Question

an engine is approaching a hill at a constant speed when it is
at a distance of 0 9km, it blows a whistle, whose echo is heard by
the driver after 5s if the speed of sound is 340m/s , find the
speed of the engine

Ashish Jain · Accepted Answer

let s be the distance travelled by engine in t sec,
acceleration of engine (a) = 0 because it is moving with constant
speed
s=ut+12at2s = 5us = v * t0 9 *1000 + 5u = 340 * 5 5u = 1700-900 =
800u =160 m/s

an engine is approaching a hill at a constant speed. when it is at a distance of 0.9km, it blows a whistle, whose echo is heard by the driver after 5s. if the speed of sound is 340m/s , find the speed of the engine