Explanation:
voltage = current × resistance
5.
12 V = 4.2 A × resistance
resistance = 12 V / 4.2 A = 2.857142857... Ohm
FYI :
4.2 A would be a lot for a small electronic device like a CD player. that would be 12×4.2 = 50.4 Watt, and the CD player would get really hot.
6.
120 V = current × 12 Ohm
current = 120 V / 12 Ohm = 10 A
Answer: 
Explanation:
Average acceleration 
is the variation of velocity 
over a specified period of time 
:
Where:
being 
the initial velocity and 
the final velocity (according to the information given from the described graph)
Then:
We actually don't need to know how far he/she is standing from the net, as we know that the ball reaches its maximum height (vertex) at the net. At the vertex, it's vertical velocity is 0, since it has stopped moving up and is about to come back down, and its displacement is 0.33m. So we use v² = u² + 2as (neat trick I discovered just then for typing the squared sign: hold down alt and type 0178 on ur numpad wtih numlock on!!!) ANYWAY....... We apply v² = u² + 2as in the y direction only. Ignore x direction.
IN Y DIRECTION: v² = u² + 2as 0 = u² - 2gh u = √(2gh) (Sub in values at the very end)
So that will be the velocity in the y direction only. But we're given the angle at which the ball is hit (3° to the horizontal). So to find the velocity (sum of the velocity in x and y direction on impact) we can use: sin 3° = opposite/hypotenuse = (velocity in y direction only) / (velocity) So rearranging, velocity = (velocity in y direction only) / sin 3° = √(2gh)/sin 3° = (√(2 x 9.8 x 0.33)) / sin 3° = 49 m/s at 3° to the horizontal (2 sig figs)
Answer:
El trabajo realizado para subir los últimos 500 metros es 318727,5 joules.
Explanation:
Por la definición de trabajo sabemos que el montañero debió contrarrestar trabajo causado por la gravedad terrestre. Si asumimos que el cambio de la altura es muy pequeño en comparación con el radio del planeta (6371 kilómetros vs. 0,5 kilómetros), entonces podemos considerar que la aceleración gravitacional es constante y la ecuación de trabajo (
), medido en joules, que reducida a:
(1)
Donde:
- Masa del montañero, medido en kilogramos.
- Aceleración gravitacional, medida en metros por segundo al cuadrado.
- Distancia vertical de ascenso del montañero, medida en metros.
Si tenemos que 
, 
y 
, entonces el trabajo realizado por el montañero para subir es:
El trabajo realizado para subir los últimos 500 metros es 318727,5 joules.
