3. Negative work on a block. A block is moving to the right in outer space while touching only an astronaut's hand, A hand exerts a constant force on the block. The work done on the block by the hand is negative. The hand's force is either to the left or to the right (but you are not told which directly). Draw arrows below to show the direction of the displacement of the block and the direction of the force by the hand Displacement of the block Force on block by hand a. Explain how you chose the direction of the force on the block by the hand. b. Does the total energy of the block increase, decrease, or stay constant? Explain, (Assume the block does not change potential energy ) Hint: Is the block speeding up, slowing down, or moving with constant speed? 4. Consider the definition of work. How do you determine if work is positive, negative, or zero? 5. You are told that in a problem, the work done on an object is -5J. Can you say anything about the direction of the object's displacement? 6. If the direction of force and displacement are known, does the sign of work change if the positive direction is reversed (e.g. positive was previously to the left and is now to the right)? Explain