Answer:
1.78 s
Explanation:
Initial speed of the ball = u = 7.95 m/s and is vertically downwards.
Acceleration due to gravity = g = 9.8 m/s/s , vertically downwards.
Height of the building h = 29.8 m (traversed downwards by the steel ball).
h = u t + 1/2 g t²
29.8 = 7.95 t + 0.5 (9.8) t²
⇒ 4.9 t² +7.95 t - 29.8 = 0
Using the quadratic formula , solve for t.
t= 
t = 
= 1.78 s, -3.4 s
Since time does not have a negative value, time taken by the stone to reach the ground = t = 1.78 s
Answer:
i = 0.3326 L
Explanation:
A fixed string at both ends presents a phenomenon of standing waves, two waves with the same frequency that are added together. The expression to describe these waves is
2 L = n λ n = 1, 2, 3…
The first harmonic or leather for n = 1
Wave speed is related to wavelength and frequency
v = λ f
λ = v / f
Let's replace in the first equation
2 L = 1 (v / f₁)
For the shortest length L = L-l
2 (L- l) = 1 (v / f₂)
These two equations form our equation system, let's eliminate v
v = 2L f₁
v = 2 (L-l) f₂
2L f₁ = 2 (L-l) f₂
L- l = L f₁ / f₂
l = L - L f₁ / f₂
l = L (1- f₁ / f₂)
.
Let's calculate
l / L = (1- 309/463)
i / L = 0.3326
Answer:
Explanation:
density (d) = 1.3 kg/m³
volume of the room (v)
= 5 m * 4m * 3 m
= 60 m³
mass(m) =?
now we know density is defined as mass per unit volume so
d = m / v
1.3 = m / 60
m = 78 kg
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