Answer:
Efficiency = 80%
Explanation:
Given the following data;
Work output = 240 N
Work Input = 300 N
To find the mechanical efficiency of a machine;
Substituting into the equation, we have;
Efficiency = 80%
Therefore, the mechanical efficiency of the machine is 80 percent.
The options of the question are missing. I have attached it.
Answer:
Satellite in option B will have the greatest speed.
Explanation:
From kepplers third law, we know that
V² = GM/R
Thus, v = √(GM/R)
Where;
v is velocity
G is gravitational constant
M is mass
R is radius
Looking at the options, let's start from the first one;
Option A
Here, mass = (1/2)m and radius = R
So, v = √(GM/R) thus v = √(G(m/2)/R) = √(Gm/2R)
Option B
Here, mass = m and radius = (1/2)R
Thus v = √(Gm/(R/2)) = √(2Gm/R)
Option C
Here, mass = m and radius = R
Thus v = √(Gm/R)
Option D
Here, mass = m and radius = 2R
Thus v = √(Gm/(2R))
Now, inspecting all the options, it's clear that option B will have the greatest velocity because it's numerator is the biggest and will in turn lead to higher velocity.
