) When did the block move with the least amount of force?

friction force acting on the block

we mustapply a force ofmagnitude80 Nto hold the block stationary at x = −2.0 cm. From that position, we then slowly move the block so that ourforce does +4.0 J of work on the spring–block system; theblock isthen again stationary.What is the block’s position?(Hint:There are two answers.)

As shown in the figure, the friction force acting on the block is

If we had added straws under the block to roll on - what do you think would have happened to the amount of force needed to move the block?  Why?

What force is needed to press the block to immerse it totally if the mass of the silver block is 1.5 kg?