How often should cardio exercises be performed? A. Never B. Three to five times a month C. Three to five times a week D. Three t
2 answers:
You might be interested in
As we know that work done is defined as product of force and displacement in the direction of applied force
so we can say it is
or we can say
so we will have following options
A)Pushing against a locked door
There is no work done in above case as there will be no displacement in that case so work done is ZERO
B) Carrying a box down a corridor
While we move done and carrying a box then work done by gravity on the box while our work done is negative work.
C) Pulling a trailer up a hill
In above case our work done to pull a box up a hill is positive work as we need to work against gravity
D) Suspending a heavy weight with a strong chain
During suspension there is no displacement so there will be no work done in above case
so correct answer will be
<em>Pulling a trailer up a hill</em>
Your answer for part a is correct. Using Newton's 3rd Law, the force on the rocket by the exhaust leaving the rocket is the same magnitude (opposite direction) as the downward force applied to the exhaust.
In part b the net force is the upward force from the exhaust thrust minus the downward force of gravity:
Then using the Second Law, we get for part c:
The force and acceleration are in the upward direction
In part b the net force is the upward force from the exhaust thrust minus the downward force of gravity:
Then using the Second Law, we get for part c:
The force and acceleration are in the upward direction