Answer:
a ) 2.68 m / s
b ) 1.47 m
Explanation:
The jumper will go down with acceleration as long as net force on it becomes zero . Net force of (mg - kx ) will act on it where kx is the restoring force acting in upward direction.
At the time of equilibrium
mg - kx = 0
x = mg / k
= (60 x 9.8 ) / 800
= 0.735 m
At this moment , let its velocity be equal to V
Applying conservation of energy
kinetic energy of jumper + elastic energy of cord = loss of potential energy of the jumper
1/2 m V² + 1/2 k x² = mg x
.5 x 60 x V² + .5 x 800 x .735 x .735 = 60 x 9.8 x .735
30 V² + 216.09 = 432.18
V = 2.68 m / s
b ) At lowest point , kinetic energy is zero and loss of potential energy will be equal to stored elastic energy.
1/2 k x² = mgx
x = 2 m g / k
= (2 x 60 x 9.8) / 800
= 1.47 m
Answer:
1 m/s² down
Explanation:
"Calculate the acceleration of the elevator, and find the direction of acceleration."
Sum of forces in the +y direction:
∑F = ma
N − mg = ma
0.9 mg − mg = ma
-0.1 mg = ma
a = -0.1 g
a = -1 m/s²
A thermos as another name - it's called the vacuum flask. It's used for<span> storing cryogens when it has certain boiling points that are much lower than the actual room temperature. Many people use thermoses as a cup for drinking, specifically coffee, teas, and other hot drinks.
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Answer: The gravitational force Fg exerted on the orbit by the planet is Fg = G 4/3πr3rhom/ (R1 + d+ R2)^2
Explanation:
Gravitational Force Fg = GMm/r2----1
Where G is gravitational constant
M Mass of the planet, m mass of the orbit and r is the distance between the masses.
Since the circular orbit move around the planet, it means they do not touch each other.
The distance between two points on the circumference of the two massesb is given by d, while the distance from the radius of each mass to the circumferences are R1 and R2 from the question.
Total distance r= (R1 + d + R2)^2---2
Recall, density rho =
Mass M/Volume V
Hence, mass of planet = rho × V
But volume of a sphere is 4/3πr3
Therefore,
Mass M of planet = rho × 4/3πr3
=4/3πr3rho in kg
From equation 1 and 2
Fg = G 4/3πr3rhom/ (R1 + d+ R2)^2
Answer:
d) It will be cut to a fourth of the original force.
Explanation:
The magnitude of the electrostatic force between the charged objects is
where
k is the Coulomb's constant
q1 and q2 are the charges of the two objects
r is the separation between the two objects
In this problem, the initial distance is doubled, so
r' = 2r
Therefore, the new electrostatic force will be
So, the force will be cut to 1/4 of the original value.
