Answer:
μ = 0.18
Explanation:
Let's use Newton's second Law, the coordinate system is horizontal and vertical
Before starting to move the box
Y axis
N-W = 0
N = W = mg
X axis
F -fr = 0
F = fr
The friction force has the formula
fr = μ N
fr = μ m g
At the limit point just before starting the movement
F = μ m g
μ = F / m g
calculate
μ = 34.8 / (19.8 9.8)
μ = 0.18
Answer:
536,904 J/s
Explanation:
The energy output from motor is the input energy in the machine.
We know that efficiency is percentage energy ouput to energy input, and expressed as

Where n and E represent efficiency and energy respectively, subscripts o and i represent output and input respectively. Since for the machine we have the input energy then the output will be the product of efficiency and input energy
Energy output=0.6*1200 hp=720 hp
Converting hp to J/s we multiply by 745.7
Energy is 720*745.7=536,904 J/s
Answer:
The maximum height is 2881.2 m.
Explanation:
Given that,
Acceleration = 29.4 m/s²
Time = 7.00 s
We need to calculate the distance
Using equation of motion

Put the value into the formula


We need to calculate the velocity
Using formula of velocity

Put the value into the formula


We need to calculate the height
Using formula of height

Put the value into the formula


We need to calculate the maximum height
Using formula for maximum height

Put the value into the formula


Hence, The maximum height is 2881.2 m.
The book is lifted upward, but gravity points down, so the work done by gravity must be negative (so you can eliminate options 1 and 3).
The force exerted on the book by gravity has magnitude
<em>F</em> = <em>mg</em> = (10 N) (9.80 m/s^2) = 9.8 N ≈ 10 N
You raise the book 1.0 m in the opposite direction, so the work done is
<em>W</em> = (10 N) (-1.0 m) = -10 J
Because it doesn't use energy it uses mechanical and kinetic