Question

• A. Train
• B. Man X
• C. Car B
• D. Man Y

Answer 1

The correct option is D

Man Y

Lets check all options Car A in moving 100 km/hr w.r.t train
= - 100 so the car can't be at rest w.r.t. train.
= - 100 =$V_A-V_t$
=$V_A-100$
As velocity of train = + 100 km/hr
⇒ - 100 = $V_A-100$
$V_A=0$
So velocity of A w.r.t ground = 0
Option B Man X is in train so his velocity as same as that of the train $V_X=100m/s$.
= 0 - 100 = - 100 = - 100 and not 0
Option C Car B
Velocity of Car B = - 100 km/hr
= $V_A-V_B$ = 0 - 100 = + 100
So A is not at rest when seen from B
Option D Man Y
$V_y=0$ w.r.t. ground as he is just standing
So car A is at rest as seen from Man Y