Answer:
The correct option is
a. v = 
Explanation:
Time at which the object start fall t = 0
The acceleration a is given by a = g - bV
Where V = Speed of the object
Speed V² = u² + 2·a·h
However with the drag force the object will approach terminal velocity as t becomes progressively larger whereby v will stop increasing
Option a. is the only option that has limiting value of v which is in the range of g as t increases ∴ option a. is the correct option.
v =
as t increases
→ 1 s and v→ g/b m/s
Answer:
f = 7.97 x 10⁶ Hz = 7.97 MHz
Explanation:
The speed of a wave is given by the following formula:

where,
v = speed of the ultrasound wave through human tissue = 1540 m/s
f = frequency of ultrasound wave required = ?
λ = wavelength of ultrasound waves = smallest detail required = 0.193 mm
λ = 0.193 mm = 1.93 x 10⁻⁴ m
Therefore,
<u>f = 7.97 x 10⁶ Hz = 7.97 MHz</u>
Answer:
u = - 38.85 m/s^-1
Explanation:
given data:
acceleration = 2.10*10^4 m/s^2
time = 1.85*10^{-3} s
final velocity = 0 m/s
from equation of motion we have following relation
v = u +at
0 = u + 2.10*10^4 *1.85*10^{-3}
0 = u + (21 *1.85)
0 = u + 38.85
u = - 38.85 m/s^-1
negative sign indicate that the ball bounce in opposite directon
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.
Answer:
0.358Kg
Explanation:
The potential energy in the spring at full compression = the initial kinetic energy of the bullet/block system
0.5Ke^2 = 0.5Mv^2
0.5(205)(0.35)^2 = 12.56 J = 0.5(M + 0.0115)v^2
Using conservation of momentum between the bullet and the block
0.0115(265) = (M + 0.0115)v
3.0475 = (M + 0.0115)v
v = 3.0475/(M + 0.0115)
plugging into Energy equation
12.56 = 0.5(M + 0.0115)(3.0475)^2/(M + 0.0115)^2
12.56 = 0.5 × 3.0475^2 / ( M + 0.0115 )
12.56 = 0.5 × 9.2872/ M + 0.0115
12.56 = 4.6436/ M + 0.0115
12.56 ( M + 0.0115 ) = 4.6436
12.56M + 0.1444 = 4.6436
12.56M = 4.6436 - 0.1444
12.56 M = 4.4992
M = 4.4992÷12.56
M = 0.358 Kg