Answer:
80%
Explanation:
Efficiency = Power output / Power input × 100 %
To calculate efficiency we need to find power output of electric pump.
We can use,
Work done = Energy change
Work done per second = Energy change per second
Work done per second = Power
Therefore, Power = Energy change per second
= Change in potential energy of water per second
=mgh / t
= 200× 10×6 / 10
= 1200 W = 1.2 kW
Now use the first equation to find efficiency,
Efficiency = × 100%
= 80 %
Answer:
57N
Explanation:
Answer:
V = 13m/s
North-East (i.e. 45 degree from North)
Explanation:
This question deals with the idea of momentum.
Since the directions of a compass are fixed, we can take south as horizontal and west as vertical. Since both pieces of coconut are of equal mass, then the resultant of the two pieces would be in between South and West and the third piece would be opposite this direction and be in the North-East (i.e. 45 degree from North) direction
To find the speed of the third piece, we first find the speed on the two pieces of the coconut in terms of (horizontal component of velocity) and
(vertical component of velocity)
We have
= Velocity in South direction = 18m/s
= Mass of piece in South direction = m
= Velocity in West direction = 18m/s
= Mass of piece in West direction = m
= Velocity of Third Piece in North direction = unknown
= Velocity of Third Piece in East direction = unknown
= Mass of third piece = 2m
Since we now know the horizontal and vertical component of the velocity of the third piece of coconut we find the resultant velocity. Since we know the direction is North-East, we can imagine a right angled triangle with base of 9 and height 9 and the hypotenuse equal to the resultant velocity .
We can simply apply the Pythagoras theorem and find the hypotenuse
V = 13m/s
