Answer: the earth
Explanation: ask your teacher
Answer:
a) Yes
b) 7 rad/s
c) 0.01034 J
Explanation:
a)
Yes the angular momentum of the block is conserved since the net torque on the block is zero.
b)
m = mass of the block = 0.0250 kg
w₀ = initial angular speed before puling the cord = 1.75 rad/s
r₀ = initial radius before puling the cord = 0.3 m
w = final angular speed after puling the cord = ?
r = final radius after puling the cord = 0.15 m
Using conservation of angular momentum
m r₀² w₀ = m r² w
r₀² w₀ = r² w
(0.3)² (1.75) = (0.15)² w
w = 7 rad/s
c)
Change in kinetic energy is given as
ΔKE = (0.5) (m r² w² - m r₀² w₀²)
ΔKE = (0.5) ((0.025) (0.15)² (7)² - (0.025) (0.3)² (1.75)²)
ΔKE = 0.01034 J
The force ffrom the ground that holds the rock up and prevents her from falling through the gound, unless the ground breaks.
Answer:
D. 9 N
Explanation:
The tension on the string is equivalent to the centripetal force.
Centripetal force is the force exerted by an object in circular motion or path towards the center of the circular path.
Centripetal force = mv²/r
where m is the mass of the object, v is the velocity and r is the radius of the circular path.
Centripetal force = (0.25 kg × 6²)/ 1
= 9 N
Thus, the tension on the string is 9 N
