Answer:7.92 N
Explanation:
Given
mass of book 
coefficient of static friction 
coefficient of kinetic friction 
To move the book, one need to overcome the static friction
Static friction 
After overcoming the Static friction , Force needed to move the block is
I'm not sure what you were trying to put here
Answer:
4000 J
Explanation:
W = F = 2000N , s = 20 m
Workdone = F × s = 200 × 20 = 4000J
Answer:
Explanation:
Given that,
Kinetic energy of an automobile is 2300J
K.E = 2300J
The formula for kinetic energy is
K.E = ½mv²
So, if the speed of the automobile is increased by 6, what is the kinetic energy
Now v' = 6v.
The mass of the automobile is constant.
Therefore, the kinetic energy is
K.E' = ½mv'²
Where v' = 6v
K.E' = ½m(6v)²
K.E' = ½m × 36v²
K.E' = 36 × ½mv²
Where, from above ½mv² = 2300J
Then,
K.E' = 36 × 2300 = 82,800J
The kinetic energy of the automobile when it increase it's speed is 82,800J
B. The reference point is the 0 of a straight line description. Left of it would be negative and right of it would be positive.
