Refer to the diagram shown below.
m = the mass of the crate.
W = mg, the weight of the crate (g = 9.8 m/s²).
N = the normal reaction from the ground.
R = 2500 N, the frictional force between the crate and the ground.
R = μN = μmg
where
μ = the static coefficient of friction
The force in the first chain is 1000 N.
Let T = the force in the second chain.
In order to move the crate, the applied force should exceed the resisting frictional force. That is,
T + 1000 ≥ 2500
T ≥ 1500 N
Because the crate does not move, T = 1500 N.
Answer: T = 1500 N
