Answer:
H / R = 2/3
Explanation:
Let's work this problem with the concepts of energy conservation. Let's start with point P, which we work as a particle.
Initial. Lowest point
Em₀ = K = 1/2 m v²
Final. In the sought height
= U = mg h
Energy is conserved
Em₀ =
½ m v² = m g h
v² = 2 gh
Now let's work with the tire that is a cylinder with the axis of rotation in its center of mass
Initial. Lower
Em₀ = K = ½ I w²
Final. Heights sought
Emf = U = m g R
Em₀ =
½ I w² = m g R
The moment of inertial of a cylinder is
I =
+ ½ m R²
I= ½
+ ½ m R²
Linear and rotational speed are related
v = w / R
w = v / R
We replace
½
w² + ½ m R² w² = m g R
moment of inertia of the center of mass
= ½ m R²
½ ½ m R² (v²/R²) + ½ m v² = m gR
m v² ( ¼ + ½ ) = m g R
v² = 4/3 g R
As they indicate that the linear velocity of the two points is equal, we equate the two equations
2 g H = 4/3 g R
H / R = 2/3
Answer:
0.91 J
Explanation:
The kinetic energy of an object is given by

where
m is the mass of the object
v is its speed
For the lemming in this problem, when he jumps, we have:
m = 0.0780 kg is the mass
v = 4.84 m/s is the speed
Substituting into the equation, we find:

Answer:
layers of cotton lining the interior
Explanation:
Answer:
7. 2 kg
8. 0.5 kg
9. 4 kg
Explanation:
The equation is F=MA
where F is force in Newtons
M is mass in kg
A is acceleration in m/s^2
for each you substitute in the F and A, and you are finding M. Meaning you divide F by A.
M = F/A
6/3 = 2
6/12 = 0.5
20/5 = 4