Answer:
the DISTANCE between the lever arm and the force is always 90º
Explanation:
In this exercise, you are asked to complete the missing words so that the phrase makes sense.
note that the torque is
τ = F x r
where bold indicates vectors
When the rope is pulled, the DISTANCE between the lever arm and the force is always 90º
Answer:
Explanation:
Given
mass of children 

distance between two children 
suppose small child is at a distance of x m from pivot point
so torque of small child and heavier child must be equal



The work done by the battery is equal to the charge transferred during the process times the potential difference between the two terminals of the battery:

where q is the charge and

is the potential difference.
In our problem, the work done is W=39 J while the potential difference of the battery is

, so we can find the charge transferred by the battery:
Answer:

Explanation:
Given that,
Angular speed of a skater, 
The moment of inertia of the skater, I = 0.6 kg-m²
We need to find the angular momentum of the skater. The formula for the angular momentum of the skater is given by :

Substitute all the values,

So, its angular momentum is equal to
.