A. Because there is still electricity going through the appliance even though it's turned off
Answer:
- 0.328J
Explanation:
POTENTIAL ENERGY = mgh
= 0.00274 × 9.81×12.2 here 2.74g = 0.00274kg
= 0.32792868 J
= 0.328J
AS IT IS BELOW THE SURFACE HENCE MUST BE NEGATIVE
hence potential energy = - 0.328J
Here in the above situation when boy pushes the girl there will be equal and opposite force on boy as per Newton's III law.
Due to this action reaction law boy will also go back with some speed.
Since there is no external force on this girl + boy system so we can use momentum conservation principle here.
As per momentum conservation
So boy will go back with speed 0.2 m/s
Part b)
Since the boy and girl will always exert same force on each other by Newton's III law so it has no it matter whether the boy pushed the girl, the girl pushed the boy, or they put their hands together and pushed each other away.
As in all above cases the as per Newton's III law the force on them is always equal and opposite.
<h2>
Answer:</h2>
Workdone = 601.33 Nm
<h2>
Explanation:</h2>
Workdone = Force(F) x horizontal distance(d).
Wordone = F x d
Where F is the horizontal component of the force
Force = 35 pounds
Recall that;
1 pound force = 4.4N
=> 35 pounds = 35 x 4.4N = 154N
=> Force = 154N
But since the rope makes a 10⁰ angle with the ground,
The horizontal component of the force F is Force x cos10⁰
=> F = 154 cos 10⁰
=> F = 154 x 0.9848
=> F = 151.66N
Horizontal distance (d) = 13 feet
Recall that;
1 foot = 0.305m
=> 13 feet = 13 x 0.305m = 3.965m
=> d = 3.965m
=> Substituting the values of F and d into the equation above, we have;
Workdone = F x d
Workdone = 151.66N x 3.965m
Workdone = 601.33Nm
