Answer:
a) 
, b) 
Explanation:
a) The Hooke's law states that spring force is directly proportional to change in length. That is to say:
In this case, the force is equal to the weight of the object:
The spring constant is:
b) The length of the spring is:
From the geometry of the problem, the 20 m-long cable creates
the hypotenuse of a right triangle, with the extended of the other two sides of
size 20 m * cos(30 deg), which is around 17.3 m. Therefore, the ball has increased
by 20 m - 17.3 m = 2.7 m.
The potential energy will have altered by m*g*h, which is 1400 kg * 9.8 m/s^2 *
1.6 m , or about 37044 joules.
Answer: the minimal force that you need to apply to move the bureau is F = 198.45N
Explanation:
If you want to move an object, you need to apply a force that is bigger than the force of the statical friction.
The force of statical friction can be written as.
Ff = k*N
where k is the coefficient of static friction, in this case, k = 0.45, and N is the normal force between the object and the surface.
In this case, the normal force is the weight of the bedroom bureau, this is:
N = m*g = 45kg*9.8m/s^2 = 441N
Then the force is:
Fr = 0.45*441N = 198.45N
This means that the minimal force that you need to apply to move the bureau is F = 198.45N
and after this point, the force of friction will work wit the kinetic coefficient of friction, that usually is smaller than the statical one.
Answer:
Explanation:
m = ρV = 1.03( 1000 kg/m³)(π(2² m²)(3.0 m)) = 12360π kg
m ≈ 38,830 kg
Answer:
26 m/s
69 m
Explanation:
Given:
v₀ = 20 m/s
a = 2 m/s²
t = 3 s
Find: v and Δx
v = at + v₀
v = (2 m/s²) (3 s) + 20 m/s
v = 26 m/s
Δx = v₀ t + ½ at²
Δx = (20 m/s) (3 s) + ½ (2 m/s²) (3 s)²
Δx = 69 m
