Question

If an engine of mass 2000 kg pulls 10 wagons each of mass 1000 kg with a force of 16000N, then the magnitude of force applied by 9th wagon on 10th wagon is ?

Answer 1

total acceleration of the system=16000/(2000+(10*1000))
where total mass of the system is= 2000+10*1000=12000kg
hence acceleration=1.33ms^2
now force of last wagon will be =ma
force will be= 1.3334*1000
force =1333.34N

Answer 2

Given:

Engine's mass,

= 2000 kg

10 wagons of mass,

= 1000 kg

Force,

= 16000 N

To find:

The magnitude of force applied = ?

Solution:

According to the question,

Total mass will be:

= $2000+10\times 1000$

= $12000 \ kg$

The total acceleration will be:

= $\frac{16000}{12000}$

= $1.33 \ m/s^2$

hence,

The last wagon's force will be:

= $ma$

= $1.3334\times 1000$

= $1333.34 \ N$

Thus the correct answer is "1333.34 N".