Answer:
i) 24.5 m/s
ii) 30,656 m
iii) 89,344 m
Explanation:
Desde una altura de 120 m se deja caer un cuerpo. Calcule a 2.5 s i) la velocidad que toma; ii) cuánto ha disminuido; iii) cuánto queda por hacer
i) Los parámetros dados son;
Altura inicial, s = 120 m
El tiempo en caída libre = 2.5 s
De la ecuación de caída libre, tenemos;
v = u + gt
Dónde:
u = Velocidad inicial = 0 m / s
g = Aceleración debida a la gravedad = 9.81 m / s²
t = Tiempo de caída libre = 2.5 s
Por lo tanto;
v = 0 + 9.8 × 2.5 = 24.5 m / s
ii) El nivel que el cuerpo ha alcanzado en 2.5 segundos está dado por la relación
s = u · t + 1/2 · g · t²
= 0 × 2.5 + 1/2 × 9.81 × 2.5² = 30.656 m
iii) La altura restante = 120 - 30.656 = 89.344 m.
Answer:
(a) Time t = 16.46 sec
(b) Time t =13.466 sec
(c) Deceleration = ![2.677m/sec^2](https://tex.z-dn.net/?f=2.677m%2Fsec%5E2)
Explanation:
(a) As the train starts from rest its initial velocity u = 0 m/sec
Acceleration ![a=1.35m/sec^2](https://tex.z-dn.net/?f=a%3D1.35m%2Fsec%5E2)
Final speed v = 80 km/hr
![80km/hr=\frac{80\times 1000}{3600sec}=22.22m/sec](https://tex.z-dn.net/?f=80km%2Fhr%3D%5Cfrac%7B80%5Ctimes%201000%7D%7B3600sec%7D%3D22.22m%2Fsec)
From first equation of motion v =u+at
So ![t=\frac{v-u}{a}=\frac{22.22-0}{1.35}=16.46 sec](https://tex.z-dn.net/?f=t%3D%5Cfrac%7Bv-u%7D%7Ba%7D%3D%5Cfrac%7B22.22-0%7D%7B1.35%7D%3D16.46%20sec)
(b) Now initial speed u = 22.22 m/sec
As finally train comes to rest so final speed v=0 m/sec
Deceleration ![a=1.65m/sec^2](https://tex.z-dn.net/?f=a%3D1.65m%2Fsec%5E2)
So ![t=\frac{v-u}{a}=\frac{0-22.22}{-1.65}=13.466 sec](https://tex.z-dn.net/?f=t%3D%5Cfrac%7Bv-u%7D%7Ba%7D%3D%5Cfrac%7B0-22.22%7D%7B-1.65%7D%3D13.466%20sec)
(c) We have given that initial velocity = 80 km/hr = 22.22 m/sec
Final velocity v = 0 m/sec
Time t = 8.30 sec
So acceleration is given by
![a=\frac{v-u}{t}=\frac{0-22.22}{8.3}=-2.6771m/sec^2](https://tex.z-dn.net/?f=a%3D%5Cfrac%7Bv-u%7D%7Bt%7D%3D%5Cfrac%7B0-22.22%7D%7B8.3%7D%3D-2.6771m%2Fsec%5E2)
As acceleration is negative so it is a deceleration
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Answer:
The answer is D 100 newton
Explanation:
2.0m/s2 is d acceleration while the 50kg is the mass. Force = mass x acceleration. So f=50x2.so force is 100 newton
Answer:
539 kPa
Explanation:
Pressure equals density times acceleration of gravity times depth.
P = ρgh
Water has a density of 1000 kg/m³, and acceleration of gravity is 9.8 m/s².
P = (1000 kg/m³) (9.8 m/s²) (55.0 m)
P = 539,000 Pa
P = 539 kPa