Question

2.) A plane is sitting on a runway, awaiting takeoff. On an adjacent parallel runway, another plane lands and passes the stationary plane at a speed of 39.4 m/s. The arriving plane has a length of 43.5 m. By looking out of a window (very narrow), a passenger on the stationary plane can see the moving plane. For how long a time is the moving plane visible?

Answer 1

Since observer is stationary and window is very narrow. So we can assume the observer as point object.

Given

Speed of plane =39.4m/s

Length of arriving plane =43.5m

Observer see the arriving plane until whole lentgh of plane pass away that is from tip to its nose to its tail.

So distnace travel =43.5m

Required time =Distance /speed=43.5/39.4

=1.10 second

Moving plane is visible for time period of 1.10 second.

Note:-if object is moving with a speed v then to travel a distnace d it takes time t=d/v.

In the above question you can apply the same logic.plane is moving with speed 39.4m/s and from tip to its nose to its tail length is 49.3 m

So Required time (t)= 49.3/39.4=1.10second.