Answer:
The rate at which this vacuum cleaner supply energy to the room when running is 285.71 Watts.
Explanation:
power efficiency of electric motor = 70% = 0.70
The power output of the vacuum cleaner =
= 200 W
The power output of the vacuum cleaner = 



The rate at which this vacuum cleaner supply energy to the room when running is 285.71 Watts.
Answer:
Velocity of ball B after impact is
and ball A is 
Explanation:
= Initial velocity of ball A

= Initial velocity of ball B = 0
= Final velocity of ball A
= Final velocity of ball B
= Coefficient of restitution = 0.8
From the conservation of momentum along the normal we have

Coefficient of restitution is given by



Adding the above two equations we get



From the conservation of momentum along the plane of contact we have


Velocity of ball B after impact is
and ball A is
.
Answer:
If there is a shaft with headgear, then mining can take place until that depth of the shaft. If it is accessed horizontal Adits, it can mine until the lowest Adit from upwards. If it is accessed decline, the development and mining can continue so long as economic exploitation is possible.
Explanation:
What are the disadvantages of mining headgear? They totally cut off your vision of anything above your head. They are hot, most of the time