Correct Answers is A.
The machines gives us some mechanical advantage. This means the mechanical average makes the work output greater than the work input
Simple most example is a lever. The force applied is smaller and the output work is larger as compared to input.
Option B cannot be true, as there must be a force to get some work done.
Option C and D are inverse of what a machine is designed for. A small force can be exerted through a large distance to have a large force exerted through a small distance. Common Example of this principle is a screw opener.
Answer:

Explanation:
From the question we are told that:
Electric Field strength 
Potential difference is 
Generally the equation for distance is mathematically given by



Answer:
75 miles an hour
I hope this is correct and helps
Answer:
Explanation:
number of turns, N = 149
radius, r = 2.15 cm
Area, A = πr² = 3.14 x 2.15 x 2.15 x 10^-4 = 1.45 x 10^-3 m^2
Change in magnetic field, ΔB = 95.5 - 50.5 = 45 mT = 45 x 10^-3 T
time, Δt = 0.165 second
induced emf
e = N x dФ/dt
where, dФ be the change in flux.
e = N x A x ΔB/Δt
e = 149 x 1.45 x 10^-3 x 45 x 10^-3 / 0.165
e = 0.058 V