Which of the following examples are producing negative work upon an object? Select all that apply. a) an upward force is applied to an object to move it downward at a constant speed.
b) an downward force is applied to an upwardmoving object to slow it down as it moves.
c) an upward force is applied to an object to suspend it motionless in mid-air.
d) a force is applied to an object to hold it at rest on a ramp.
e) a rightward force is applied to an object to move it to the right at a constant speed. ​