First, you find what 20% of 10 gallons of gas would be. This will show how many gallons the car actually uses.
10 gallons x 20% =
10 x 0.20 =
2 gallons used
Then you subtract that number from the total 10 gallons to get how many gallons of gas would be wasted.
10 gallons - 2 gallons =
8 gallons of gas wasted
Answer:

Explanation:
Uncertainty principle say that the position and momentum can not be measured simultaneously except one relation which is described below,

Given that the uncertainty in x is 0.1 mm.
Therefore,

Therefore, uncertainty in the transverse momentum of photon is 
To solve this problem it is necessary to apply the concepts related to the Moment. The moment in terms of the Force and the time can be expressed as

F = Force

At the same time the moment can be expressed in terms of mass and velocity, mathematically it can be given as

Where
m = Mass
Change in velocity
Our values are given as

By equating the two equations we can find the Force,



Therefore, the net average force will be:

The negative symbol indicates that the direction of the force is upwards.
B.gold also known as the famous gold foil experiment