A machine can never be 100% efficient because some work is always lost
due to the lack of materials or equipment that would convert work by 100%. It follows
the second law of entropy. The ideal engine is known as Carnot’s engine having
a 100% efficiency. So far, no engine has ever gotten to 100%.

Actually Welcome to the Concept of the Projectile Motion.
Since, here given that, vertical velocity= 50m/s
we know that u*sin(theta) = vertical velocity
so the time taken to reach the maximum height or the time of Ascent is equal to
T = Usin(theta) ÷ g, here g = 9.8 m/s^2
so we get as,
T = 50/9.8
T = 5.10 seconds
thus the time taken to reach max height is 5.10 seconds.
Assuming it's an ideal material, the answer is A.
The speed of sound depends on the medium that the sound travels through.
Answer:
v=77.62 m/s
Explanation:
Given that
h= - 300 m
speed of the bird ,u= 5 m/s
Lets take Speed of the berry when it hit the ground = v m/s
we know that ,if object is moving upward
v² = u² - 2 g h
u=Initial speed
v=Final speed
h=Height
Now by putting the values
v² = u² - 2 g h
v² = 5² - 2 x 10 x (-300) ( take g = 10 m/s²)
v² =25 + 20 x 300
v² ==25 + 6000
v² =6025
v=77.62 m/s
Therefore the final speed of the berry will be 77.62 m/s.
The expression for the radius and height of the cone can be obtained from
the property of a function at the maximum point.
- The height of the cone is half the length of the radius of the circular sheet metal.
Reasons:
The part used to form the cone = A sector of a circle
The length of the arc of the sector = The perimeter of the circle formed by the base of the cone.

θ/360·2·π·s = 2·π·r
Where;
s = The radius of he circular sheet metal
h = s² - r²
3·r²·s² - 4·r⁴ = 0
3·r²·s² = 4·r⁴
3·s² = 4·r²


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