mech... plz help

a train A runs from east to west and another train B of the same mass runs from west to east at the same speed along the equator. A presses the track with a force F1 and B presses the track with a force F2, then

(a) F1>F2
(b) F1<F2
(c) F1 = F2

i can' t find any hint in the qst to find the relation b/w F1 and F2

7 Answers

71
Vivek @ Born this Way ·

Hint : The train moving in a direction opposite to the motion of train will wear out it's wheels faster.

39
Dr.House ·

earth spins from west to east

the frictional force proportional to normal force also has to balance that

11
Khyati ·

If the frame of reference is perfectly inertial, then both the forces are definitely equal.

However, you got to keep in mind that earth is not an inertial frame of reference for it

rotates about its own axis giving it something called centripetal acceleration. So, when you sit

on earth and observe both the trains, then there exists a pseudo force on the trains, also

called centrifugal force.

As you might know, earth rotates from west to east. The train moving in this direction will

have more apparent velocity by frame of reference and as a result it will

experience more centrifugal force(acting outward) and will have lesser weight than the

train moving in an inertial frame. Using similar argument, the train moving from east to west

will have more weight than the train moving in an inertial frame.

Hence, F1 > F2.

1
venkateshan ·

i understood wht khyati said....thanks.... but is it true wht vivek is saying....

1
nihal raj ·

no...

71
Vivek @ Born this Way ·

The train moving in a direction opposite to the motion of earth will wear out it's wheels faster.

This gives the same result as of Khyati's I think.

Made a mistake.

71
Vivek @ Born this Way ·

Doubts:

earth rotates from west to east. The train moving in this direction will

have more apparent velocity

Both moving in same direction, then their relative velocities should have been a difference of the two na?

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