Option A looks like the best definition
Answer:
Power is the rate at which work is done
Explanation:
Power is the rate at which work is done. Power is measured in watts.
Work is the use of force to move an object. Work is measured in joules.
Answer:
25.06s
Explanation:
Remaining part of the question.
(A large stone sphere has a mass of 8200 kg and a radius of 90 cm and floats with nearly zero friction on a thin layer of pressurized water.)
Solution:
F = 60N
r = 90cm = 0.9m
M = 8200kg
Moment of inertia for a sphere (I) = ⅖mr²
I = ⅖ * m * r²
I = ⅖ * 8200 * (0.9)²
I = 0.4 * 8200 * 0.81
I = 2656.8 kgm²
Torque (T) = Iα
but T = Fr
Equating both equations,
Iα = Fr
α = Fr / I
α = (60 * 0.9) / 2656.8
α = 0.020rad/s²
The time it will take her to rotate the sphere,
Θ = w₀t + ½αt²
Angular displacement for one revolution is 2Π rads..
θ = 2π rads
2π = 0 + ½ * 0.02 * t²
(w₀ is equal to zero since sphere is at rest)
2π = ½ * 0.02 * t²
6.284 = 0.01 t²
t² =6.284 / 0.01
t² = 628.4
t = √(628.4)
t = 25.06s
Answer:
Hooke's law, given by 
is denoted with a negative sign to regard that the direction of restoring force that occurs opposite in direction of the force that caused the displacement 
. F represents the force required to create a spring displacement of .
Explanation:
As with many things in physics, the negative sign represents direction. In this case, after a spring is displaced a distance of from equilibrium, the restoring force created by the spring will be in opposite direction of the force applied to move the spring there, represented by F.
Answer:
The speed is constant.
Speed is a scalar quantity (magnitude only).
Velocity is a vector quantity (magnitude and direction).
For an object in Uniform Circular Motion the change in velocity is always
directed towards the center of the circle, and this change of velocity
gives rise to the acceleration which is directed towards the center of
rotation. This is called the centripetal acceleration, and it is the centripetal
force (for instance the attraction of the moon towards the earth) which
produces the centripetal acceleration.
