Answer:
Δy = 7.1 cm
Explanation:
The center of mass of a body is defined
= 1 /M ∑
i
Where M is the total mass of the body, m mass of each part and ‘y’ height
Let's apply this equation to our case
We locate the reference system on the shoulders
The height of the arms is at its midpoint
y = -75/2 = 37.5 cm
With arms down
= 1/70 (63 y₀ - 3.5 37.5 - 3.5 37.5)
= 1/70 (63 y)₀ - 7 37.5)
With arms up
’= 1/70 (63 y₀ + 3.5 y + 3.5 y)
’= 1/70 (63y₀ + 7 35.5)
let's subtract the two equations
’ - = 1/70 2 (7 35.5)
Δy = ’ - = 2 7 35.5 / 70
ΔY = 7.1 cm
Answer:
Work is done by the heart on the blood during this time is 0.04 J
Explanation:
Given :
Mass of blood pumped, m = 80 g = 0.08 kg
Initial speed of the blood, u = 0 m/s
Final speed of the blood, v = 1 m/s
Initial kinetic energy of blood is determine by the relation:
Final kinetic energy of blood is determine by the relation:
Applying work-energy theorem,
Work done = Change in kinetic energy
W = E₂ - E₁
Substitute the suitable values in the above equation.
W = 0.04 J
I believe it is the first one
Explanation:
6000 years = 6000 x 365 x 24 x 60 x 60
= 1.892 x 10¹¹ second
gain is 1 second
1 second is equivalent to 9.193 × 10⁹ oscillations .
In 1.892 x 10¹¹ second , change in oscillation is 9.193 × 10⁹ oscillation
in one second change in oscillation = (9.193 / 1.892 ) x 10⁹⁻¹¹
= 4.859 x 10⁻² oscillations .
