A vehicle covers certain distance at constant speed of 20 km h^(-1) in time interval 't' on linear path. Then it covers certain distance at constant speed of 30 km h^(-1)in the same time interval. What is the average speed of the vehicle ?

A vehicle covers certain distance at constant speed of 20 km h^(-1) in

1.	A vehicle covers certain distance at constant speed of 20 km h^(-1) in time interval 't' on linear path. Then it covers certain distance at constant speed of 30 km h^(-1)in the same time interval. What is the average speed of the vehicle ?
Answer» Solution :Here `v _(j) v _(g) and v _(0)` are velocities of jet plane, combustion products ejected and observer on ground respectively. Suppose, jet plane is moving in +X-axis, Ejected combustion products are in -X-axis, Now `v _(j) = 500` km/hr `v _(0) = 0` (At REST) Velocity of jet plane w.r.t observer, `=v _(j)- v _(0) = 500 -0` ` = 50 km//hr. ""...(1)` Velocity of combustion products w.r.t jet plane, `v _(g) -v_(j) = - 1500 km.//hr.""...(2)` `v _(g) - v _(0) = 500 - 1500 = - 1000 km//hr` Velocity of ejected combustion products by observer on ground in opposite to jet plane is 1000 km/hr.