Answer:
Explanation:
Let the internal resistance be r .
Since in open circuit the volt is 1.55 V , this will be the source voltage .
Source voltage = 1.55
If external resistance be R .
1.55 / (R + r ) = .500
R + r = 3.1 ohm
So sum of internal resistance and external resistance will be 3.1 ohm.
Answer:
6.4m/s
Explanation:
The total mechanical energy of the man is 1780J.
This mechanical energy is the energy due to the motion of the body and it is a form of kinetic energy.
Also, mass = 87kg
Kinetic energy = 
m v²
m is the mass
v is the velocity
1780 = x 87 x v²
v² = 40.9
v = 6.4m/s
<span>The working formula to analyze this problem is
Vf^2 - Vo^2 = 2gs
where
Vf = velocity at which the gymnast hits the ground
Vo = initial velocity of the gymnast (given as 4 m/s and -3 m/s)
g = acceleration due to gravity = 9.8 m/sec^2 (constant)
s = height at which gymnast starts her dismount
For the first dismount,
Vf^2 - (4)^2 = 2(9.8)(s)
Vf^2 = 16 + 19.6s
and for the second dismount,
Vf^2 - (-3)^2 = 2(9.8)(s)
Vf^2 = 9 + 1.6s
Since "s" is the same for both dismounts, then her final velocity in the first dismount is higher than that of her second dismount.</span>
