Answer:
(i) The maximum acceleration upward is 2.02 m/s².
(ii) The maximum acceleration downward is 1.39 m/s².
Explanation:
Let a be the maximum acceleration of the elevator.
The mass of the person at ground is 150 lb. We have to convert the mass into kg,
1 lb = 0.453592 kg
150 lb = 68 kg
170 lb = 77 kg
120 lb = 54 kg
(i) The person experience a force due to Earth's gravity in the downwards direction. The magnitude of this force is:
F₁ = mg = 68 x 9.8 = 666.4 N
The weight of the person decreases as the elevator is moving upwards. So, the force experienced by the person in this case due to gravity is:
F₂ = 54 x 9.8 = 529.2 N
Applying Newton's force equation;
(F₁ - F₂) = ma
(666.4 - 529.2) = 68 x a
a = 2.02 m/s²
(ii) The weight of the person increases as the elevator is moving downwards. So, the force experienced by the person in this case due to gravity is:
F₂ = 77 x 9.8 = 754.6 N
Applying Newton's force equation;
(F₁ - F₂) = ma
(666.4 - 754.6) = 68 x a
a = -1.30 m/s²
Draw a vector diagram. The net force on particle 1 = F12 + F13 + F14 These forces have to be added as vectors.
We will resolve our forces along the direction 1-4 F12 (tot) = -kQq / a^2 in the direction of particle 4 F12 = -kQq *sin (45) / a^2 F12 = -kQq /( a^2 * sqrt(2) )
By symetry this is the same as F13 F13 = -kQq /( a^2 * sqrt(2) )
F14 = -kQQ / (Sqrt(2)*a) ^ 2
For net force on particle 1 :
F12+F13+F14 = 0 -2kQq /( a^2 * sqrt(2) ) + -kQQ / (Sqrt(2)*a) ^ 2 = 0
Some simple manipulation should give you :
Q/q = -2 sqrt(2)
Answer:
your answers are correct i have done this many times
Yes. True. Resistors slow the current down at the point in the circuit.
Hope it helps you...
( Answered by Benjemin )
Answer:
Fb = 941.76 [N]
Explanation:
La fuerza de flotacion se define como el producto de la densidad del liquido por la aceleración gravitacional y por el volumen desplazado
Fb = Ro*g*V
donde:
Fb = fuerza de flotacion [N] (unidades del Newtons)
Ro = densidad del liquido = 1000 [kg/m³]
g = aceleracion gravitacional = 9.81 [m/s²]
V = volumen desplazado = 0.096 [m³]
Reemplazando:
Fb = 1000*9.81*0.096
Fb = 941.76 [N]
