Question

Question 3.5:
A jet airplane travelling at the speed of 500 km h–1 ejects its products of combustion at
the speed of 1500 km h–1 relative to the jet plane. What is the speed of the latter with
respect to an observer on ground?

Answer 1

Answer:

Answer 3.5: [ncert 11 motion in straight line]

Speed of the jet airplane, vjet = 500 km/h

Relative speed of its products of combustion with respect to the plane,

vsmoke = – 1500 km/h

Speed of its products of combustion with respect to the ground = v′smoke

Relative speed of its products of combustion with respect to the airplane,

vsmoke = v′smoke – vjet

1500 = v′smoke – 500

v′smoke = – 1000 km/h

The negative sign indicates that the direction of its products of combustion is opposite to

the direction of motion of the jet airplane.