In: Physics
1)An object experiences a force in the direction opposite its motion. This means
the work vector points in the negative direction
the scalar value of work is negative
the scalar vector of work could be either positive or negative, depending on which direction is chosen to be positive.
the work vector could point in either the positive or negative direction, depending on which direction is chosen to be positive.
2: A hand lifts a block vertically upward at constant velocity. The work done by gravity on the block ____ if the system consists of the block only. The work done by gravity on the block ____ if the system consists of the block and the earth. AND WHY?
is zero, is zero/is zero, is negative/is zero, is positive/is negative, is negative/is positive, is positive
3: A block of mass M is moves down a frictionless ramp of angle θ and height H. The block is pushed at the top of the ramp so that its initial speed is 4 m/s.
Consider system A to be only the block and system B to be the block and the earth together. Is the speed of the block at the bottom of the ramp in system A ______to the speed of the block at the bottom of the ramp in system B?
greater than, less than, or equal