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secondary 3 | Physics
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Example 9. Tysm
= mg
= 4.0 x 10
= 40 N
[On earth, g = 10 N/kg]
Object moves with a constant VELOCITY, so object is not accelerating at all (a = 0).
By F = ma and using the fact that a = 0, the resultant horizontal force acting on the object must be zero.
This means that the object's forward force is equal to the frictional force, but the object is sliding on a "smooth" (counted as frictionless) surface, so there is not even a need for any applied force to get the object moving at constant velocity.
So, zero force is required to keep the block moving.
The resultant force acting on the object must be zero as well (not just the horizontal portion) because the block does not simply "sink into the ground" due to its weight.
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