As shown in the figure, the height of the inclined plane is 1m and the length is 3M. The worker pushes the 840n box onto the car with 400N force along the inclined plane. What is the useful work done by the worker in this process___ J. What is the mechanical efficiency___ %If the slope is smooth, the required thrust is___ N．

As shown in the figure, the height of the inclined plane is 1m and the length is 3M. The worker pushes the 840n box onto the car with 400N force along the inclined plane. What is the useful work done by the worker in this process___ J. What is the mechanical efficiency___ %If the slope is smooth, the required thrust is___ N．

(1) When the box is pushed to the top of the inclined plane, the useful work is: Wye = GH = 840n × 1m = 840j. (2) the length of the inclined plane is 3M, and the thrust force is 400N. When the box is pushed to the top of the inclined plane, the total work of the thrust force is: wtotal = FS = 400N × 3M = 1200J. The mechanical efficiency of the inclined plane is: η = Wye = 840j1200j = 70%. If the inclined plane is smooth, GH = f's, so 840n × 1m = f '× 3M So the answer is: 840; 70; 280

The height of the inclined plane is 1m and the length is 3M. The workers use 400N force along the inclined plane to push the 840n box onto the vehicle at a speed of 0.5m/s
The height of the inclined plane is 1m and the length is 3M. The worker pushes the 840n box onto the car at a speed of 0.5m/s with 400N force along the inclined plane. What is the useful work done by the worker in this process___ J. The power of the worker's work is____ W. What is the mechanical efficiency____ At this time, the friction force of the inclined plane to the box is___ N?

1. The purpose is to raise an object to a height of 1 meter, so the work done to raise an object to a height of 1 meter is useful work
W = GH = 840n x 1m = 840j
2. The work done by the worker is multiplied by the force used by the worker and the distance of the object moving up the force: wtotal = FS = 400nx 3M = 1200J
3. Mechanical efficiency: η = w / W total = 840j / 1200J = 70%
4. At this time, the friction force on the inclined plane of the box is 400N, because the speed of the object moves in a straight line, that is to say, the force is balanced, and the thrust and friction force are balanced, so the two forces are the same size, 400N

If m ^ 2 + M-1 = 0, find the value of - m ^ 3-2m ^ 2 + 2011

m^2+m-1=0 m^2+m=1
-m^3-2m^2+2011
=-m(m^2+m+m)+2010
=-m(1+m)+2011
=-(m^2+m)+2011
=-1+2011
=2010

M ^ 2 + M-1 = 0, then m ^ 3 + 2m ^ 2 + 1 is equal to?
Such as the title

m^2 + m - 1 = 0
m^2 + m = 1
m^3 + 2m^2 + 1 = m(m^2 + m) + m^2 + 1
= m + m^2 + 1
= 1 + 1
= 2

Given a ^ 3 * a ^ m * a ^ 2m + 1 = a ^ 25, find the value of (M-8) ^ 2010

a^3*a^m*a^2m+1
=a^(3+m+2m+1)
=a^(4+3m)
4+3m=25
3m=21
m=7
(m-8)^2010
=(7-8)^2010
=(-1)^2010
=1

M ^ 2 + M = 1, find the value of m ^ 3 + 2m + 2010

M ^ 2 + M = 1 is m ^ 2 + 2 = 3-m
Original formula = m (m ^ 2 + 2) + 2010 = m (3-m) + 2010 = - m ^ 2 + 3M + 2010
From m ^ 2 + M = 1, we get - m ^ 2 + 3M = 4m-1
Then the above formula = 4m + 2009
From m ^ 2 + M = 1, M = ± √ 5 / 2-1 / 2
So the original formula = ± 2 √ 5 + 2007

If M-N = 1, then 2m - (n-m) ^ 2010-2 (n-3)=_______ .
Thank you. I don't quite understand. Would you please tell me the process?
I got 5, but it's not right, ha ha, trouble ~!

2m-(n-m)^2010-2(n-3)
=2m-2n+6-(n-m)^2010
=2(m-n)+6-(n-m)^2010
=2*1+6-(-1)^2010
=8-1
=7

Given m ^ 2 + m - 1 = 0, the process and explanation of calculating the value of m ^ 3 + 2m ^ 2 + 2007

Because m ^ 2 + m - 1 = 0, m ^ 2 + M = 1
Multiply the left and right sides of m ^ 2 + M = 1 by m to get m ^ 3 + m ^ 2 = M. add m ^ 2 to the left and right sides to get m ^ 3 + m ^ 2 = M
M ^ 3 + 2m ^ 2 = m ^ 2 + m, so m ^ 3 + 2m ^ 2 = 1
So m ^ 3 + 2m ^ 2 + 2007 = 1 + 2007 = 2008

Given that a = m-2 M-1, B = - 2 M-3, we can find the value of 2a-3b when m = - 2

When m = - 2
A=4+4-1=7
B=-8-3=-11
2A-3B=14+33=47

Mathematical problem 1 / M + 1 / N = 7 / M + N, then n / M-M / N =?

1/m+1/n=(m+n)/mn=7/(m+n)
(m+n)²=7mn
m²+n²+2mn=7mn
m²+n²=5mn
therefore
n/m+m/n
=(n²+m²)/mn
=5mn/mn
=5