# college physics

posted by .

A 2.0 kg disc rolls without slipping on a horizontal surface, so that its center of mass has a constant linear speed of 6.0 m/s. What is the total kinetic energy of the disc?

i know that k= 0.5mv2 + 0.5 I w2
K=1/2 mv2 (1+(I/mr2)

but i am still getting he wrong answer because i convert I to miri2 so therefore it cancels with the denominator and k = 1/2mv2 but that is wrong. i am stuck

• college physics -

I for a solid disc is (1/2) m r^2

Try it with that.

If you use I = m r^2 (which would be correct for a hoop), you would get
total KE = mv^2, not(1/2) m v^2

## Similar Questions

1. ### physics

A 10.0-kg cylinder rolls without slipping on a rough surface. At the instant its center of amss has a speed of 10m/s, determine (a) the translational kinetic of its center of mass (b) the rotational kinetic energy about its center …
2. ### Physics

A hollow sphere of radius 0.30 m, with rotational inertia I = 0.080 kg m2 about a line through its center of mass, rolls without slipping up a surface inclined at 19° to the horizontal. At a certain initial position, the sphere's …
3. ### physics

A hollow sphere of radius 0.30 m, with rotational inertia I = 0.072 kg m2 about a line through its center of mass, rolls without slipping up a surface inclined at 25° to the horizontal. At a certain initial position, the sphere's …
4. ### physics

a bowling ball has a mass of 8kg. if it rolls down the alley, without slipping, at 7m/s, calculate a) the linear kinetic energy, b) the rotaional kinetic energy, c) the total kinetic engergy

A 10.0 kg cylinder rolls without slipping on a rough surface. At an instant when its center of gravity has a speed of 16.0 m/s, determine (a) the translational kinetic energy of its center of gravity.(b) the rotational kinetic energy …
6. ### Physics

A student puts on a Dresden Dolls disc in her cd player which spins at 1800 revolutions per minute. A compact disc has a mass of about 0.016 kg and a radius of 6.0 cm. a) What is the period of rotation in seconds?
7. ### Physics

A student puts on a Dresden Dolls disc in her cd player which spins at 1800 revolutions per minute. A compact disc has a mass of about 0.016 kg and a radius of 6.0 cm. a) What is the period of rotation in seconds?
8. ### physics

A student puts on a Dresden Dolls disc in her cd player which spins at 1800 revolutions per minute. A compact disc has a mass of about 0.016 kg and a radius of 6.0 cm. a) What is the period of rotation in seconds?
9. ### mit

1 point possible) A uniform disc of radius R and mass m1 is rotating with an angular speed ωi about an axis passing through its center and perpendicular to the disc's plane. A small box of mass m2, initially at the center of the …
10. ### physics

Question Part Submissions Used A 11.5-kg cylinder rolls without slipping on a rough surface. At an instant when its center of gravity has a speed of 10.9 m/s, determine the following. (a) the translational kinetic energy of its center …

More Similar Questions