A 2.6 kg block is attached to a horizontal rope that exerts a variable force Fx=(20−5x)N, where x is in m. The coefficient of kinetic friction between the block and the floor is 0.25. Initially the block is at rest at x = 0 m.

What is the block's speed when it has been pulled to x=1.4m?

The block's speed when it has been pulled to x=1.4m is v = 3.28 m/s

According to the work energy theorem we know that total work done is equivalent to change in kinetic energy of the system.

v = 3.28

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Speed of the block after it is pulled a distance x = 1.4 m is v = 3.28 m/s

Explanation:

As per work energy theorem we know that total work done is equal to change in kinetic energy of the system

so here we have

so we will have

its a 5.5 n

glad that