1. An object has the momen inersia of 1 kg m2 rotates at a constant angular speed of 2 rad/dtk. What is the rotational kinetic energy tina objék éta?
Dipikanyaho:
Momen inersia (I) = 1 kg m2
nu laju sudut (ω) = 2 rad/dtk
miharep: The rotational kinetic energy (KE)
Solusi:
The formula of the rotational kinetic energy :
KE = 1/2 Abdi ω2
KE = the rotational kinetic energy (kg m²)2/s2), I = the moment of inertia (kg m²)2), ω = the angular velocity (rad/s)
The rotational kinetic energy :
KE = 1/2 I ω2 = 1/2 (1)(2)2 = 1/2 (1)(4) = 2 Joule
2. Beurat 20 kg cylinder pulley with a radius of 0.2 m rotates at a constant angular speed of 4 rad/s. What is the rotational kinetic energy of the pulley?
Dipikanyaho:
massa of cylinder pulley (M) = 20kg
The radius of cylinder (r) = 0.2 m
Kecepatan sudutna (ω) = 4 rad/s
Dipilari: What is the rotational kinetic energy
Solusi;
Formula of the moment inertia of cylinder :
I = 1/2 mr2
Abdi = the moment of inertia (kg m2), m = massa (kg), r = radius (meter)
Momen inersia katrol silinder:
Kuring = 1/2 (20)(0.2)2 = (10)(0.04) = 0.4 kg m²2
The rotational kinetic energy of the pulley :
KE = 1/2 I ω2 = 1/2 (0.4)(4)2 = (0.2)(16) = 3.2 Joule
3. A-10 kg ball with radius of 0.1 m rotates at a constant of 10 rad/dtk. What is the kinetic energy of the ball.
Dipikanyaho:
massa bal (M) = 10 kg
Radius bal (r) = 0.1 m
Laju sudut (ω) = 10 riklan
Dipilari: The rotational kinetic energy
Solusi:
Formula of the moment of inertia :
I = (2/5) Bapa.2
Abdi = momen inersia (kg m²)2), m = massa (kg), r = radius (M)
Moment of inertia of the ball :
Abdi = (2/5)(10)(0.1)2 = (4)(0.01) = 0.04 kg m²2
The rotational kinetic energy of the ball :
KE = 1/2 I ω2 = 1/2 (0.04)(10)2 = (0.02)(100) = 2 Joule
4. A 0.5-kg particle rotates at a constant angular speed of 2 rad/dtk. What is the rotational kinetic energy of the particle if the radius of circle is 10 cm.
Dipikanyaho:
massa of particle (M) = 0.5kg
The radius of ball (r) = 10 cm = 10/100 = 0.1 m
Kecepatan sudutna (ω) = 2 rad/s
Dipilari: The rotational kinetic energy
Solusi:
Moment of inertia for particle :
I = Pa.2 = (0.5)(0.1)2 = (0.5)(0.01) = 0.005 kg m²2
The rotational kinetic energy :
KE = 1/2 I ω2 = 1/2 (0.005)(2)2 = 1/2 (0.005)(4) = (0.005)(2) = 0.01 Joule
