A force F is required to push a crate along a rough horizontal floor at a constant speed V with friction present.
What force is needed to push this crate along the same floor at a constant speed 3V if friction is the same as before?
A. A constant force 3F is needed.
B. A force that gradually increases from F to 3F is needed.
C. A constant force F is needed.
D. No force is needed, since the crate has no acceleration.
good
GOOD
None
To determine the force needed to push the crate along the same floor at a constant speed 3V, we need to consider the relationship between force, friction, and speed.
When the crate is moving at a constant speed, the force pushing the crate (the applied force) is equal and opposite to the force of friction. This means that F = friction.
Since we are assuming that the friction remains the same, F remains the same as in the previous scenario when the speed was V.
Therefore, the force needed to push the crate along the same floor at a constant speed 3V is the same as before, which is a constant force F.
Therefore, the correct answer is:
C. A constant force F is needed.