Page 6 of 9
Re: Machines B/C
Posted: October 14th, 2019, 12:15 pm
by Umaroth
A ball with mass 7.50 kg reaches the base of a ramp with a slope of 30.0 degrees at a velocity of 15.0 m/s. If it rolls up a distance of 5.75 m before stopping, what is the coefficient of friction of the ramp?
Re: Machines B/C
Posted: October 14th, 2019, 7:13 pm
by AlfWeg
Umaroth wrote: ↑October 14th, 2019, 12:15 pm
A ball with mass 7.50 kg reaches the base of a ramp with a slope of 30.0 degrees at a velocity of 15.0 m/s. If it rolls up a distance of 5.75 m before stopping, what is the coefficient of friction of the ramp?
About
1.73? By sum of forces or energy...
Re: Machines B/C
Posted: October 14th, 2019, 7:23 pm
by Umaroth
AlfWeg wrote: ↑October 14th, 2019, 7:13 pm
Umaroth wrote: ↑October 14th, 2019, 12:15 pm
A ball with mass 7.50 kg reaches the base of a ramp with a slope of 30.0 degrees at a velocity of 15.0 m/s. If it rolls up a distance of 5.75 m before stopping, what is the coefficient of friction of the ramp?
About
1.73? By sum of forces or energy...
Ah, I messed up, I meant 15.75 m, not 5.75, you did it correctly but I messed up the problem. With 15.75 m you should get
0.264.
Re: Machines B/C
Posted: October 15th, 2019, 5:03 am
by shrewdPanther46
EDIT nvm
Re: Machines B/C
Posted: October 16th, 2019, 3:22 am
by AlfWeg
A ramp is 5 meters high and 13 meters long. A solid sphere is released at the top of the inclined plane. Friction is negligible. Calculate velocity at the bottom of the ramp. Assume g = 10
m/s^2. Edit: I made a mistake in this question
Re: Machines B/C
Posted: October 16th, 2019, 7:55 am
by Umaroth
AlfWeg wrote: ↑October 16th, 2019, 3:22 am
A ramp is 5 meters high and 13 meters long. A solid sphere is released at the top of the inclined plane. Friction is negligible. Calculate velocity at the bottom of the ramp. Assume g = 10
m/s^2.
ans is not V=sqrt(2gh)
10 m/s
Re: Machines B/C
Posted: October 16th, 2019, 8:14 am
by AlfWeg
Umaroth wrote: ↑October 16th, 2019, 7:55 am
AlfWeg wrote: ↑October 16th, 2019, 3:22 am
A ramp is 5 meters high and 13 meters long. A solid sphere is released at the top of the inclined plane. Friction is negligible. Calculate velocity at the bottom of the ramp. Assume g = 10
m/s^2.
ans is not V=sqrt(2gh)
10 m/s
Edit: Made a mistake in the question. Ur right!
Your turn!
Re: Machines B/C
Posted: October 16th, 2019, 10:07 am
by shrewdPanther46
AlfWeg wrote:
Umaroth wrote: ↑October 16th, 2019, 7:55 am
AlfWeg wrote: ↑October 16th, 2019, 3:22 am
A ramp is 5 meters high and 13 meters long. A solid sphere is released at the top of the inclined plane. Friction is negligible. Calculate velocity at the bottom of the ramp. Assume g = 10
m/s^2.
ans is not V=sqrt(2gh)
10 m/s
I think you missed that it's a sphere and it's rolling, so we have to include rotational kinetic energy in our energy equation. Taking that into Consideration, We get [KE (translational) + KE (Rotational) = PE] The formula for rotational KE is (1/2 * Rotational Inertia * Omega^2 ). A solid sphere has a rpt. Inertia of (2/5) * Mass * (Radius^2) and Omega = V/R. Thus, we get the equation
(1/2) * M * V^2 + (1/2) * (2/5) *M * R^2 = M* G*H. Rearranging we get, v = sqrt((10/7)gh), giving us 8.5 m/s^2. This Presentation might help to understand this.
Your turn!
Umaroth's solution is correct, the sphere has no reason to roll
Re: Machines B/C
Posted: October 16th, 2019, 11:50 am
by AlfWeg
shrewdPanther46 wrote: ↑October 16th, 2019, 10:07 am
AlfWeg wrote:
Umaroth wrote: ↑October 16th, 2019, 7:55 am
10 m/s
I think you missed that it's a sphere and it's rolling, so we have to include rotational kinetic energy in our energy equation. Taking that into Consideration, We get [KE (translational) + KE (Rotational) = PE] The formula for rotational KE is (1/2 * Rotational Inertia * Omega^2 ). A solid sphere has a rpt. Inertia of (2/5) * Mass * (Radius^2) and Omega = V/R. Thus, we get the equation
(1/2) * M * V^2 + (1/2) * (2/5) *M * R^2 = M* G*H. Rearranging we get, v = sqrt((10/7)gh), giving us 8.5 m/s^2. This Presentation might help to understand this.
Your turn!
Umaroth's solution is correct, the sphere has no reason to roll
Oh lol I forgot to say it was rolling. Ignore my stupidity
Re: Machines B/C
Posted: November 21st, 2019, 12:26 pm
by terence.tan
what is the ideal mechanical advantage of an Archimedes screw?