Spring Force

IMPORTANT

Spring Force: Overview

This topic covers concepts such as Spring Forces, Parallel Arrangement of Springs, Series Arrangement of Springs, Cutting of Springs in a Ratio, Arrangement of Springs, Effective Force Constant, and Effect of Cutting of Springs and Strings in System.

Important Questions on Spring Force

MEDIUM
IMPORTANT

If ks and kp respectively are effective spring constant in series and parallel combination of springs as shown in the figure, find  k s k p

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EASY
IMPORTANT

A light spring of force constant 8 Nm-1 is cut into two equal halves and the two are connected in parallel; the equivalent force constant of the system is

EASY
IMPORTANT

A light spring of constant k is cut into two equal parts. The spring constant of each part is

EASY
IMPORTANT

In a spring-mass system, the length of the spring is L, and it has a mass M attached to it and oscillates with an angular frequency ω. The spring is then cut into two parts, one (a) with relaxed length αLand the other (b) with relaxed length 1-αL. The force constants of the two springs A and B are

EASY
IMPORTANT

When, two ends of an ideal spring are pulled apart increasing its length it produces force equal to kx at its ends. At a point 14 of its length from one end, the force is

EASY
IMPORTANT

Two blocks A&B with mass 4 kg and 6 kg respectively are connected by a stretched spring of negligible mass as in figure. When the two blocks are released simultaneously the initial acceleration of B is 1.5 m/s2 westward. The acceleration of A is:

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MEDIUM
IMPORTANT

Two springs of force constants 300 N/m (Spring A) and 400 N/m (Spring B) are joined together in series. The combination is compressed by 8.75 cm. The ratio of energy stored in A and B is EAEB. Then EAEB is equal to:

EASY
IMPORTANT

In a HCl molecule, the Cl can be treated on infinite mass and H oscillating alone. If the oscillation of HCl molecule shows frequency of 7×1013 s-1, the value of force constant is (take Avogadro number=6×1026 per kg-mole)

MEDIUM
IMPORTANT

The system shown in the figure is released from rest. Pulley and spring are massless and friction is absent everywhere. The speed of 5 kg block when 2 kg block leaves the contact with ground is K=40 N m-1 & g=10 m s-2

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EASY
IMPORTANT

A mass m is suspended by two springs of force constants K1 and K2 respectively as shown in the diagram. The total elongation (stretch) of the two springs is

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EASY
IMPORTANT

What will be time period of the displaced body of mass m ?

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MEDIUM
IMPORTANT

A trolley of mass 3 kg is connected to two identical springs of spring constant 600 N m-1 as shown in the figure. The trolley is displaced from its equilibrium position by 5 cm and released. Find the maximum speed of the trolley in the ensuing motion. 
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HARD
IMPORTANT

A solid cylinder of mass 3 kg is rolling on a horizontal smooth surface with velocity 4ms-1. It strikes with a fixed horizontal spring of force constant 200Nm-1 . The maximum compression produced in the spring is

MEDIUM
IMPORTANT

In an elevator, a system is arranged as shown in the figure. Initially, the elevator is at rest and the system is in equilibrium with the middle spring unstretched. When the elevator accelerates upwards, it was found that for the new equilibrium position (with respect to the lift), the further extension in the top spring is 1.5 times that of the further compression in the bottom spring irrespective of the value of acceleration.

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If k1=k2=k3=500 N m-1 and m1=2 kg and the acceleration of the elevator is 2.5 m s-2find the tension in the middle spring in final equilibrium with respect to the lift.

HARD
IMPORTANT

A spring of force constant K is fixed at one end and has a small block of mass m and charge q attached at the other end. The block rests over a smooth horizontal surface. A uniform and constant magnetic field B exists in space normal to the plane of the figure. Also an electric field E=E0i^ is switched on at t = 0 sec where E0 is a positive constant. If the block moves on horizontal surface without ever lifting off the surface then the normal reaction acting on the block is-


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MEDIUM
IMPORTANT

You are riding in an automobile of mass 3000 kg. Assuming that you are examining the oscillation characteristics of its supension system. The suspension sags 15 cm when the entire automobile is placed on it. Also, the amplitude of oscillation decreases by 50 % during one complete oscillation. Estimate the value of the spring constant k.

HARD
IMPORTANT

Match the Column I with Column II:

  Column - I   Column - II
(a) Question Image (i)

T=2πmk1+k2k1k2  

(b) Question Image (ii)

T=2π2 mk

(c) Question Image (iii)

T=2πm2 k

(d) Question Image (iv) T=2πmk1+k2

MEDIUM
IMPORTANT

A trolley of mass 3 kg, as shown in figure, is connected to two identical springs, each having spring constant equal to 600 N m-1. If the trolley is displaced from its equilibrium position by 5 cm and released, the maximum speed of the trolley is:
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HARD
IMPORTANT

In the system shown in figure M1>M2 and pulley and threads are ideal. System is held at rest by thread BC. Just after thread BC is burnt,

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MEDIUM
IMPORTANT

Two springs are connected to a block of mass M placed on a frictionless surface as shown below. If both the springs have a spring constant k, then the frequency of oscillation of the block is

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