Answer:
Newton's third law of motion states that every action has an equal and opposite reaction. This indicates that forces always act in pairs. Reaction forces are equal and opposite, but they are not balanced forces because they act on different objects so they don't cancel each other out.
Answer:
During the section CD , the speed is fastest.
Explanation:
The rate of change of distance is called speed.
Speed = distance / time
Its SI unit ism/s. It is a scalar quantity.
The slope of the distance time graph is given by the speed of the object.
Here, the speed of AB is 30/3= 10 m/s .
The speed of BC is = 0 m/s
The speed of CD is (50 - 30)/(6 - 5) = 20 m/s
So, the speed is maximum during the section CD.
Answer:
is a reflection.
The image is real light rays actually focus at the image location). As the object moves towards the mirror the image location moves further away from the mirror and the image size grows (but the image is still inverted). When the object is that the focal point, the image is at infinity.
Explanation:
Newton's second law of motion describes what happens to a body when an external force is applied to it.
Newton's second law of motion states that the force acting on an object is equal to the mass of that object times its acceleration. In mathematical form this is written as
F = ma
Where F is force , m is mass and a is acceleration. The math or logic behind this is that if you double the force, you double the acceleration, but if you double the mass, you cut the acceleration in half.
Answer:
distance is 13 m for 100 dB
distance is 409 km for 10 dB
Explanation:
Given data
distance r = 2.30 m
source β = 115 dB
to find out
distance at sound level 100 dB and 10 dB
solution
first we calculate here power and intensity and with this power and intensity we will find distance
we know sound level β = 10 log(I/
) ......................a
put here value (I/) = 10^−12 W/m² and β = 115
115 = 10 log(I/10^−12)
so
I = 0.316228 W/m²
and we know power = intensity × 4π r² ...............b
power = 0.316228 × 4π (2.30)²
power = 21.021604 W
we know at 100 dB intensity is 0.01 W/m²
so by equation b
power = intensity × 4π r²
21.021604 = 0.01 × 4π r²
so by solving r
r = 12.933855 m = 13 m
distance is 13 m
and
at 10 dB intensity is 1 × 10^–11 W/m²
so by equation b
power = intensity × 4π r²
21.021604 = 1 × 10^–11 × 4π r²
by solving r we get
r = 409004.412465 m = 409 km
