Question

A jet plane travel at a speed of 500 km per hour exact it product of combinations at the speed of 1500 km per hour relative to the jet plane what is the speed of letter with respect to an observer on ground​

Answer 1

Question :

A Jet airplane traveling at the speed of 500 km/h ejects its products of combustion at the speed of 1500km/h relative to the Jet plane. What is the speed of the latter with respect to an observer on the ground ?

Solution :

• Velocity of Jet = 500 km/h
• Relative speed of ejection of products wrt jet plane = - 1500 km

Here , relative speed of ejection of products wrt jet plane is taken as negative, as it is in the opposite direction of the motion.

We have to find Speed of latter wrt observer .

Let speed of latter wrt observer be $\sf{(V_o)}$ , velocity of jet be $\sf{(V_j)}$ and relative speed of ejection of products wrt jet plane be $\sf{(V_c)}$

$\implies \sf{V_c \: = \: V_o \: - \: V_j} \\ \\ \implies \sf{V_o \: = \: V_c \: + V_o} \\ \\ \implies \sf{V_o \: = \: -1500 \: + \: 500} \\ \\ \implies \sf{V_o \: = \: - \: 1000}$

We will took velocity as positive as it negative because of opposite direct but, Speed of latter with respect to ground is 1000 km/h

Answer 2

Question:-

A jet airplane travelling at the speed of 500 km\h ejects gases at a speed of 1000km\h the speed of the gas relative to rocket is or (speed of latter by seen by a observer in the ground.)

Explanation:

Given,

$\Large\vec{v}_{j}\:= \: 500\:Km\:h^{-1}$

$\Large\vec{v}_{cj}\:=\: -1500 \:Km\:h^{-1}h$

( Note:- here velocity of cumbustion or gas in negative direction)

To Find :-

$\vec{v}_{c}\:=\:?$

Solution:-

$\vec{v} _{cj} =\vec{v}_{c} - \vec{v}_{j} \\ - 1500 =\vec {v} _{c} - 500 \\ - 1500 + 500 = \vec{v} _{c} \\ ➜\vec{v} _{c} = - 1000$

Note:-

$\vec{v}_{cj}$ is Velocity of cumbustion with respect to jet.

$\vec{v}_{c}$ is Velocity of cumbustion respect to the ground which we are finding.

$\vec{v}_{j}$ is Velocity of jet.

Velocity of cumbustion in 1000 Km\h in opposite direction in plane.

The speed of gas is 1000km\hr or latter

Or,

The speed observe by the observer is 1000 Km\h.

Here, All statements are correct.