Torsion Pendulum
Product Code : EL-AM-10317
Quick answer: The Torsion Pendulum is a solid brass disc, 12.5 cm in diameter and 1.25 cm thick, hung from a universal clamp by a wire held in a chuck nut at each end, with a heavy brass ring of the same outside diameter. It is used to find the rigidity modulus of the wire and the moment of inertia of the disc. Lab Exports manufactures it in Delhi for schools, colleges and universities.
Specifications
| Component | Specification |
|---|---|
| Disc | Solid brass, 12.5 cm diameter, 1.25 cm thick |
| Ring | Heavy brass, same outside diameter as the disc |
| Suspension | Wire held by a chuck nut at each end, hung from a universal clamp |
| Alternate size | Also available with a 6 inch brass disc |
How the torsion pendulum experiment is done
Twisted and released, the disc performs torsional oscillations with period T = 2 pi sqrt(I/C), where I is its moment of inertia and C the torsional constant of the wire. Placing the ring on the disc adds a known moment of inertia, I_ring = M (R1^2 + R2^2)/2 for a ring of mass M with inner and outer radii R1 and R2, and lengthens the period. Two periods and one known addition are enough to find both I and C without knowing either in advance.
- Clamp the wire in the chuck nuts, hang the disc from the universal clamp and let it come to rest.
- Twist the disc through a small angle and time 20 oscillations to find T0.
- Place the brass ring centrally on the disc and time 20 oscillations again to find T1.
- Weigh the ring and measure its radii, then measure the length l and radius r of the wire.
The moment of inertia of the disc is I0 = I_ring T0^2 / (T1^2 - T0^2), and the modulus of rigidity of the wire is eta = 8 pi l I_ring / [r^4 (T1^2 - T0^2)].
Key features
- Solid brass disc, 12.5 cm in diameter and 1.25 cm thick
- Heavy brass ring of the same outside diameter adds a calculable moment of inertia
- Chuck nut at each end of the wire for firm, repeatable clamping
- Hangs from a universal clamp
- Also available with a 6 inch brass disc
Documentation and supply
Installation instructions and a manual are supplied with the apparatus. Most Lab Exports products carry a one-year manufacturer warranty.
Lab Exports manufactures the Torsion Pendulum at its works in Laxmi Nagar, Delhi, and supplies it to schools, colleges and universities in India and 60+ countries, handling the export documents for each shipment. More about the company is on the About Lab Exports page.
Related Applied Mechanics products
- Fly Wheel (EL-AM-10316)
- Torsion Pendulum (Bridge Type) (EL-AM-10318)
- Inertia Disc (EL-AM-10315)
- Torsion Apparatus Searle's Type (EL-AM-10319)
- Inertia Table (EL-AM-10314)
- Torsion (Barton's) Apparatus Vertical Pattern (EL-AM-10320)
The full range is in the Applied Mechanics section of the Physics Lab range.
Frequently asked questions
What does the brass ring do in the torsion pendulum?
Placed on the disc, it increases the moment of inertia and therefore the period of vibration, which lets both the moment of inertia of the disc and the rigidity of the wire be calculated.
What size is the torsion pendulum disc?
The standard disc is solid brass, 12.5 cm in diameter and 1.25 cm thick; a version with a 6 inch brass disc is also available.
What is the price of the Torsion Pendulum?
Prices are not published on the website. Add the Torsion Pendulum to the Enquiry Cart with the Add To Cart button on this page, or email [email protected] with the house code EL-AM-10317 and the quantity, to receive a quotation.
Does Lab Exports manufacture the Torsion Pendulum?
Yes. Lab Exports manufactures the Torsion Pendulum at its works at 11/315, Lalita Park, Laxmi Nagar, Delhi 110092, under house code EL-AM-10317.
Request a quote
Email [email protected] with the house code EL-AM-10317 and the quantity, or add the Torsion Pendulum to the Enquiry Cart with the Add To Cart button on this page. Tender buyers can also see the Tenders and OEM page.
