Answer:
a one bucket with full of sand because of it's mass which plays role in momentum
B is the answer because a solid would not be able to hold its shape if it was able to move around
Answer:
1. t = 3.27 seconds
2. y = 147.3 m
Explanation:
Newton's Laws of Motions.
y = v₁t + 1/2 at²
a = (v₂-v₁)/t
where
y = the vertical distance travelled
v₁ = the initial velocity
v₂ = the final velocity
t = the time
a = the acceleration
final velocity is equal to 0.
So, v₂ = 0.
a = (v₂-v₁)/t
a = (0-30)/t
a = -30/t
plugin values into the first equation:
y = v₁t + 1/2 at²
49 = 30t + 1/2 (-30/t)t²
49 = 30t -15t
49 = 15 t
t = 49/15
t = 3.27 seconds
2.
y = v₁t + 1/2 at²
a = -30/3.27
a = 9.2
y = 30(3.27) + 1/2(9.2) 3.27²
y = 147.3 m
Answer:
the moment of inertia with the arms extended is Io and when the arms are lowered the moment
I₀/I > 1 ⇒ w > w₀
Explanation:
The angular momentum is conserved if the external torques in the system are zero, this is achieved because the friction with the ice is very small,
L₀ = L_f
I₀ w₀ = I w
w =
w₀
where we see that the angular velocity changes according to the relation of the angular moments, if we approximate the body as a cylinder with two point charges, weight of the arms
I₀ = I_cylinder + 2 m r²
where r is the distance from the center of mass of the arms to the axis of rotation, the moment of inertia of the cylinder does not change, therefore changing the distance of the arms changes the moment of inertia.
If we say that the moment of inertia with the arms extended is Io and when the arms are lowered the moment will be
I <I₀
I₀/I > 1 ⇒ w > w₀
therefore the angular velocity (rotations) must increase
in this way the skater can adjust his spin speed to the musician.
Answer:
The speed of the kid and the skateboard together is 0.723 m/s
Explanation:
Let the mass of the kid be 
Let the mass of the skateboard be 
The initial speed of the skateboard, 
The initial horizontal speed of the boy as he jumps on the skateboard, 
Let the speed of the kid and the skateboard together be v
According to the principle of conservation of momentum:

Substituting the appropriate values into the given equation

36 = 49.8 v
v = 36/49.8
v = 0.723 m/s