Answer:
η = 0.667 = 66.7%
Explanation:
The efficiency of the man can be given by the following formula:
η = output/input
where,
η = efficiency of man = ?
output = potential energy gain of the box = Wh
input = work done by man = Fd
Therefore,
where,
W = weight of box = 200 N
h = height gained by box = 1 m
F = force exerted by man = 60 N
d = length of ramp = 5 m
Therefore,
<u>η = 0.667 = 66.7%</u>
Answer:
The force required will be "300 N".
Explanation:
The given values are:
Mass of object,
m = 300 kg
Acceleration,
a = 1 m/s
Now,
The force will be:
⇒
On substituting the values, we get
⇒
⇒
Given that,
At 3.00 m from a source that is emitting sound uniformly in all directions, the sound level is 60.0 dB.
To find,
The distance from the source would the sound level be one-fourth the sound level at 3.00 m.
Solution,
The intensity from a source is inversely proportional to the distance.
Let I₁ = 60 dB, r₁ = 3 m, I₂ = 60/4 = 15 dB, r₂ =?
Using relation :
So, at a distance of 6 m the sound level will be one fourth of the sound level at 3 m.