Resolving the forces for an object suspended on two strings.

Imagine a following situation: a stationary (not moving) object with a mass of 5 kg is suspended in the air by two strings. The angles between strings and the vertical directions are 15 and 55 degrees. What are tensions T1 and T2 in both strings?The first thing to do would be just drawing a simple diagram. I don't think it's possible to add one here, but I drew a little diagram myself! Now, we have to resolve the forces in the horizontal and vertical directions. Because the object is stationary, according to Newton's laws of dynamics we know that adding all the forces will equal 0. Let's start!Vertical forces: we have two vertical components of tension T1 and T2 pointing upwards (call it +ve direction) and weight i.e. 5g pointing downwards (let's take g = 9.8). So: T1cos(15o) + T2cos(55o) - 59.8 = 0  (eqn. 1)Horizontal forces: one component points to the left (-ve direction), the other to the right (+ve direction). Hence: T1sin(15o) - T2sin(55o) = 0  (eqn. 2)We can see equations 1 and 2 form a set of simultaneous equations. Let's rearrange 2 to get T1 in terms of T2: T1 = T2sin(55o) / sin(15o)  (eqn. 3).Substituting equation 3 into equation 1 gives: T2sin(55o)*cot(15o) + T2cos(55o) = 49  (eqn. 4) .From equation 4: T2 = 13.5 N and hence from equation 3: T1 = 42.7 N.

Answered by Filip W. Physics tutor

17591 Views

See similar Physics A Level tutors

Related Physics A Level answers

All answers ▸

Why is a pendulum with a bob of the same size but larger mass than another bob damped more lightly?


An ice cube with a small iron ball in its centre is placed in a cup of water. 3.9 x 10-3kg of water in the cup is displaced and the volume of the ice cube is 4.0 x 10-6m3. Ice density: 1000 kg m-3 Iron density: 7800 kg m-3, what is the volume of the iron?


Explain the advantages of a reflecting telescope compared to a refracting telescope


A cannon ball is fired at an angle 30 degrees from horizontal from a cannon with a speed 30km/h, a) calculate how high the cannonball flies, and the horizontal distance from the cannon the cannonball reaches


We're here to help

contact us iconContact usWhatsapp logoMessage us on Whatsapptelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

© MyTutorWeb Ltd 2013–2025

Terms & Conditions|Privacy Policy
Cookie Preferences