If an object is moving at a constant velocity, is there no work done on that object?

If there is a constant velocity, then, #∆E = 0#, which implies that #W=0#. Am I wrong?

2 Answers
Aug 2, 2017

No work is done as acceleration is zero

Explanation:

If an object moves with constant velocity,
#vec a# = #vec 0#

#vec F = m*vec a#

#rArr vec F= vec 0#

#W=F*S#

#:.W=0#

Aug 2, 2017

The total work done on the object is indeed #0#.

Explanation:

If an object is moving with a constant velocity, then by definition it has zero acceleration.

And according to Newton's second law,

#sumF = ma#

#sumF = m(0) = 0#

So there is no net force acting on the object.

The simple equation for total work is

#W_"tot" = sumF·s#

Since the net force #sumF# is #0#,

#W_"tot" = 0·s = color(blue)(ulbar(|stackrel(" ")(" "0" ")|)#

The total work done on the object is thus #color(blue)(0# (that's not to say that there isn't work done by individual forces on the object, but the sum is #0#).