Solve Physics Problem: 500g Rock on 1m String Tilt Down at 10 Degrees

  • Thread starter Thread starter rooster_17
  • Start date Start date
  • Tags Tags
    Physics Urgent
AI Thread Summary
A 500g rock tied to a 1.0-m string tilts down at a 10-degree angle while being swung in a horizontal circle. To find the angular velocity, the centripetal force equation, Fc = mv^2/r, is used alongside gravitational force considerations. The linear velocity is calculated using v = gtanθ, resulting in a vertical component of 1.70 m/s. However, the horizontal component is determined to be 0 m/s, leading to an angular velocity of 0 rad/s. Therefore, the rock does not tilt down at all under these conditions.
rooster_17
Messages
4
Reaction score
0
This might be an easy problem, but I am missing something and am not sure where to start so here is the problem:

A student ties a 500g rock to a 1.0-m-long string and swings it around her head in a horizontal circle. At what angular velocity, does the string tilt down at a 10 degree angle?

If anyone can help me get going on this problem I would greatly appreciate it.
 
Physics news on Phys.org
Draw a diagram and consider gravity and the centrifugal 'force' on the rock.
The net force must make a 10 degree angle with the horizontal.
 


To solve this physics problem, we can use the equation for centripetal force, Fc = mv^2/r, where Fc is the centripetal force, m is the mass of the rock, v is the velocity, and r is the radius of the circle (in this case, the length of the string). We also know that the force of gravity, Fg, is acting on the rock, causing it to tilt downwards.

To find the angular velocity, we can use the equation ω = v/r, where ω is the angular velocity, v is the linear velocity (which we can find using the given angle and radius), and r is the radius.

First, let's find the linear velocity. We can use trigonometry to find the horizontal and vertical components of the velocity. The horizontal component will be the same as the linear velocity, while the vertical component will be the velocity caused by the tilt of the string.

Using the given angle of 10 degrees, we can find the vertical component of the velocity using the equation v = gtanθ, where g is the acceleration due to gravity (9.8 m/s^2) and θ is the angle. Plugging in the values, we get v = 9.8m/s^2 * tan(10 degrees) = 1.70 m/s.

To find the horizontal component, we can use the Pythagorean theorem, v^2 = vhorizontal^2 + vvertical^2. Plugging in the values, we get vhorizontal = √(v^2 - vvertical^2) = √(1.70^2 - 1.70^2) = 0 m/s.

Now, we can use the equation ω = v/r to find the angular velocity. Plugging in the values, we get ω = 0 m/s / 1.0 m = 0 rad/s.

In conclusion, the angular velocity at which the string will tilt down at a 10 degree angle is 0 rad/s. This means that the rock will not tilt down at all, as the horizontal component of the velocity is 0 m/s. I hope this helps you understand and solve the problem.
 
I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19. For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...
Thread 'A cylinder connected to a hanging mass'
Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
Back
Top