The hint is "constant speed".
If there is a net force on an object, what occurs to that object? F net = m*a.... It accelerates!
So, if the desk is going at a CONSTANT speed, what does that tell you about the acceleration? There is a change in speed.
Fnet = m*a Since a = 0 Fnet = 0
Fnet = sum of the force... reflect the direction of F as the positive direction. Sum of the forces in the direction of F = 0 0 = F - friction F = friction
So, if F = 800 N, then friction = 800 N in the opposite direction.
All 3 objects have the same mass
<span>System B: The amorphous silicon solar modules have an efficiency of 6%. The dimensions of the solar modules amount to 0.5m by 1.0m. The output of each module is 30 Wp. The modules cost 20€ each. The advanage of the amorphous silicon solar modules is that they perform better on cloudy days in which there is no direct sunlight. Installed in the Netherlands, this system gives, on a yearly basis, 10% more output per installed Wp than the multicrystalline silicon modules. </span>
<span>System A: The efficiency of the multicrystalline silicon module amounts to 15%. The dimensions of the solar module are 0.5m by 1.0m. Each module has 75 Wp output. The modules cost 60€ each.
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Answer: Fourth option. It increased by a factor of 3.
Solution:
m1=1.0 kg
Cylinder's gravitational potential energy: Ep=m*g*h
Ep1=(1.0 kg)*g*h
Ep1=g*h
m2=3.0 kg
Ep2=(3.0 kg)*g*h
Ep2=3*g*h
Replacing g*h by Ep1 in the equation above:
Ep2=3*Ep1
Then, the cylinder's gravitational potential energy increased by a factor of 3.
I did try to solve. I hope it is correct, below is the solution:
<span>put everything in s.i units
then the answer what u wrote is acceleration to get is divide by mass(80)
G=6.011*10^-11
M=6*10^24
R=6.4*10^6
m=80
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Hope it helps.