Explanation:
Efficiency is defined as the ratio between the useful output over the total amount consumed. 
The fan does 500W of useful work while wasting 300 W. The total power consumption is 800 W (500 + 300).
Answer:
kg
Explanation:
easy question to be honest
Hello!

Use the equation:

Where:
m = mass of the object (kg)
g = acceleration due to gravity (≈9.8 m/s)
h = height above ground (m)
Plug the given values into the equation:
PE = 7500 · 9.8 · 100
PE = 7,350,000 Joules.
Answer:
80.4 N
Explanation:
As the block is at rest on the slope, it means that all the forces acting on it are balanced.
We are only interested in the forces that act on the block along the direction perpendicular to the slope. Along this direction, we have two forces acting on the block:
- The normal reaction N (contact force), upward
- The component of the weight of the block,
, downward, where m is the mass of the block, g is the gravitational acceleration and
is the angle of the incline
Since the block is in equilibrium along this direction, the two forces must balance each other, so they must be equal in magnitude:

And by substituting the numbers into the equation, we find the size of the contact force normal to the slope:
