Answer:
10.52 m
Explanation:
The power radiated by a body is given by
P = σεAT⁴ where ε = emissivity = 0.97, T = temperature = 30 C + 273 = 303 K, A = surface area of human body = 1.8 m², σ = 5.67 × 10⁻⁴ W/m²K⁴
P = σεAT⁴ = 5.67 × 10⁻⁸ W/m²K⁴ × 0.97 × 1.8 m² × (303)⁴ = 834.45 W
This is the power radiated by the human body.
The intensity I = P/A where A = 4πr² where r = distance from human body.
I = P/4πr²
r = (√P/πI)/2
If the python is able to detect an intensity of 0.60 W/m², with a power of 834.45 W emitted by the human body, the maximum distance r, is thus
r = (√P/πI)/2 = (√834.45/0.60π)/2 = 21.04/2 = 10.52 m
So, the maximum distance at which a python could detect your presence is 10.52 m.
Answer:
1.08 s
Explanation:
From the question given above, the following data were obtained:
Height (h) reached = 1.45 m
Time of flight (T) =?
Next, we shall determine the time taken for the kangaroo to return from the height of 1.45 m. This can be obtained as follow:
Height (h) = 1.45 m
Acceleration due to gravity (g) = 9.8 m/s²
Time (t) =?
h = ½gt²
1.45 = ½ × 9.8 × t²
1.45 = 4.9 × t²
Divide both side by 4.9
t² = 1.45/4.9
Take the square root of both side
t = √(1.45/4.9)
t = 0.54 s
Note: the time taken to fall from the height(1.45m) is the same as the time taken for the kangaroo to get to the height(1.45 m).
Finally, we shall determine the total time spent by the kangaroo before returning to the earth. This can be obtained as follow:
Time (t) taken to reach the height = 0.54 s
Time of flight (T) =?
T = 2t
T = 2 × 0.54
T = 1.08 s
Therefore, it will take the kangaroo 1.08 s to return to the earth.
Let us consider two vectors A and B.
As per the question, the two vectors are perpendicular to each other.
Hence the angle between them 
We are asked to calculate the resultant of these two vectors.
As per parallelogram law of vector addition, the resultant of two vectors are-
[cos90=0]
This is the way by which we can add two perpendicular vectors.
Answer:
false statement : b ) For the motion of a cart on an incline plane having a coefficient of kinetic friction of 0.5, the magnitude of the change in kinetic energy equals the magnitude of the change in gravitational potential energy
Explanation:
mechanical energy = potential energy + kinetic energy = constant
differentiating both side
Δ potential energy + Δ kinetic energy = 0
Δ potential energy = - Δ kinetic energy
first statement is true.
Friction is a non conservative force so inter-conversion of potential and kinetic energy is not possible in that case. In case of second option, the correct relation is as follows
change in gravitational potential energy = change in kinetic energy + work done against friction .
So given 2 nd option is incorrect.
In case of no change in gravitational energy , work done is equal to
change in kinetic energy.
<h3>Answer</h3>
6.6 N pointing to the right
<h3>Explanation</h3>
Given that,
two forces acting of magnitude 3.6N
angle between them = 48°
To find,
the third force that will cause the object to be in equilibrium
<h3>1)</h3>
Find the vertical and horizontal components of the two forces
vertical force1 = sin(24)(3.6)
vertical force2= -sin(24)(3.6)
<em>(negative sign since it is acting on opposite direction)</em>
vertical force3 = sin(24)(3.6) - sin(24)(3.6)
= 0
<h3>2)</h3>
horizontal force1 = cos(24)(3.6)
horizontal force2= cos(24)(3.6)
horizontal force3 = cos(24)(3.6) + cos(24)(3.6)
= 2(cos(24)(3.6))
= 6.5775 N
≈ 6.6 N
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