Answer:
The force is 
Explanation:
The diagram for this question is shown on the first uploaded image
From the question we are told that
The weight of the gate is 
The vertical component of F is 
From the diagram , taking moment about the pivot we have

Where
is the weight of the gate evaluated as

=> 
=> 
=> 
The magnitude of the kinetic friction force, ƒk, on an object is. Where μk is called the kinetic friction coefficient and |FN| is the magnitude of the normal force of the surface on the sliding object. The kinetic friction coefficient is entirely determined by the materials of the sliding surfaces. hope it helps
Answer:
when the momentum of the vehicle moving at 30 km/h is higher than the one from the vehicle moving at 60 km/h
Explanation:
It's much harder to stop a freight truck moving at 30 km/h than a hot wheels car moving at 60 km/h.