a) 2.75 s
The vertical position of the ball at time t is given by the equation
where
h = 4 m is the initial height of the ball
u = 12 m/s is the initial velocity of the ball (upward)
g = 9.8 m/s^2 is the acceleration of gravity (downward)
We can find the time t at which the ball reaches the ground by substituting y=0 into the equation:
This is a second-order equation. By solving it for t, we find:
t = -0.30 s
t = 2.75 s
The first solution is negative, so we discard it; the second solution, t = 2.75 s, is the one we are looking for.
b) -15.0 m/s (downward)
The final velocity of the ball can be calculated by using the equation:
where
u = 12 m/s is the initial (upward) velocity
g = 9.8 m/s^2 is the acceleration of gravity (downward)
t is the time
By subsisuting t = 2.75 s, we find the velocity of the ball as it reaches the ground:
And the negative sign means the direction is downward.
Answer:
4.22 m
Explanation:
Una rampa es una máquina que se utiliza para levantar un objeto con una fuerza menor a la que realmente necesitarías. Cuanto mayor sea la longitud de la rampa, menor será la magnitud de la fuerza necesaria para levantar el objeto.
Dado que:
altura de la rampa = 1.5 m, carga = 4900 N, fuerza aplicada = 1633.33 N.
La fórmula de la rampa se da como:
fuerza aplicada * longitud de la rampa = peso de la carga * altura de la rampa
1633.33 * longitud de la rampa = 4900 * 1.5
longitud de la rampa = 4900 * 1.5 / 1633.33
longitud de la rampa = 4.22 m
it will experience great force
Answer: Δβ (dB) = -13.1dB
Explanation:
The intensity of sound is inversely proportional to the square of the distance between them.
I ∝ 1/r²
I₁/I₂= r₂²/r₁² .....1
When the listener increases his distance from the source by a factor of 4.49.
Then,
r₂/r₁= 4.49
From equation 1
I₁/I₂ = (4.49)²
I₁/I₂ = 20.16
I₂/I₁ = 1/20.16
The change in sound intensity in dB can be given as
Δβ (dB) = 10 log(I₂/l₁) = 10log(1/20.6) = -13.1dB
<span>procedure would most likely help determine a chemical property of the substance is : exposing it to a flame to see if it catches on fire
Chemical property is the characteristic that a substance has that differntiate it with another substance. The most common charatcteristics that most scientists wanted to know are :
- It's flamability
- It's radioactivity
- Its toxicity
By throwing the object into fire, we will easily find out these 3 characteristics</span>
