Centripetal force is given by F= mv²/r.
Given: m = 0.5 kg, v = 3 m/s, r = 0.5 m
Putting values,
F= mv²/r = 0.5× 3²/0.5 = 9 N
Answer:

Explanation:
As we know that the acceleration of a point on the rim of the disc is in two directions
1) tangential acceleration which is given as

2) Centripetal acceleration

here we know that


now we know that net linear acceleration is given as

so we have


Answer:
B.
It will be greater than 10 J.
Explanation:
The total mechanical energy of an object is the sum of its potential energy (PE) and its kinetic energy (KE):
E = PE + KE
According to the law of conservation of energy, when there are no frictional forces on an object, its mechanical energy is conserved.
The potential energy PE is the energy due to the position of the object: the highest the object above the ground, the highest its PE.
The kinetic energy KE is the energy due to the motion of the object: the highest its speed, the largest its KE.
Here at the beginning, when it is at the top of the roof, the baseball has:
PE = 120 J
KE = 10 J
So the total energy is
E = 120 + 10 = 130 J
As the ball falls down, its potential energy decreases, since its height decreases; as a result, since the total energy must remain constant, its kinetic energy increases (as its speed increases).
Therefore, when the ball reaches the ground, its kinetic energy must be greater than 10 J.
The kinetic energy is given by:

We know the mass and the maximum speed, plugging their values in the expression above we have:

Therefore, the answer is d.
Explanation:
(D) i think there you go have a good day