Answer:
M = 0.31 kg
Explanation:
This exercise must be done in parts, let's start by finding the speed of the set arrow plus apple, for this we define a system formed by the arrow and the apple, therefore the forces during the collision are internal and the moment is conserved
let's use m for the mass of the arrow with velocity v₁ = 20.4 m / s and M for the mass of the apple
initial instant. Just before the crash
p₀ = m v₁ + M 0
instant fianl. Right after the crash
p_f = (m + M) v
p₀ = p_f
m v₁ = (m + M) v
v = (1)
now we can work the arrow plus apple set when it leaves the child's head with horizontal speed and reaches the floor at x = 8 m. We can use kinematics to find the velocity of the set
x = v t
y = y₀ + t - ½ g t²
when it reaches the ground, its height is y = 0 and as it comes out horizontally,
0 = h - ½ g t²
t² = 2h / g
For the solution of the exercise, the height of the child must be known, suppose that h = 1 m
t =
t = 0.452 s
let's find the initial velocity
v = v / t
v = 8 / 0.452
v = 17.7 m / s
From equation 1
v = m / (m + M) v₁
m + M =
M = m + m \ \frac{v_1}{v}
we calculate
M = 0.144 + 0.144
M = 0.31 kg
They got back in the Lunar Explorer Module
Answer:
Definimos:
Rapidez media es igual al cociente entre la distancia recorrida y el tiempo que se tarda en recorrer esa distancia.
En este caso la distancia recorrida es 400m, y el tiempo que se tarda es 30s, entonces la rapidez media va a ser:
RM = 400m/30s = 13.33 m/s
La velocidad media por otro lado, es igual al cociente entre el desplazamiento y el tiempo necesario para desplazarse.
El desplazamiento es igual a la distancia entre la posición final y la posición inicial, que en este caso eso 40m, y el tiempo necesario sigue siendo 30s, entonces la velocidad media va a ser:
VM = 40m/30s = 1.33 m/s
The correct answer for this is A. <span>Accompany her to talk with your parents or another trusted adult to ask for help
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Answer:
v = 8.90 km/h
Explanation:
In order to calculate the maximum collision speed of the 1200kg car, you take into account that the the kinetic energy of the car when it has a speed v, is equal to the potential elastic energy of the spring when it is maximum compressed.
Then, you use the following equation:
(1)
M: mass of the car = 1200kg
v: maximum collision speed of the car = ?
k: spring constant = 1.5MN/m = 1.5*10^6 N/m
x: maximum compression supported by the spring = 7.0cm = 0.070m
You solve the equation (1) for v and replace the values of the other parameters:
In km/h you obtain:
The maximum collision that the car can support is 8.90km/h