JEE Main · 2023 · 06 Apr 2023 · Shift 1 · Laws of Motion

A small block of mass 100 g is tied to a spring of spring constant

7.5 N / m

and length 20 cm. The other end of spring is fixed at a particular point A. If the block moves in a circular path on a smooth horizontal surface with constant angular velocity

5 rad / s

about point A, then tension in the spring is

(A)1.5 N
(B)0.75 N✓ Correct
(C)0.25 N
(D)0.50 N

Answer: (B)

Solution

Let the extension in the spring be

x

. The radius of the circular path is

r = 0.2 + x

meters.

The spring force provides the centripetal force:

k x = m ω^{2} r = m ω^{2} (0.2 + x)

Substituting values (

m = 0.1

kg,

k = 7.5

N/m,

ω = 5

rad/s):

7.5 x = 0.1 \times 25 \times (0.2 + x)

7.5 x = 2.5 (0.2 + x)

7.5 x = 0.5 + 2.5 x

5 x = 0.5

x = 0.1 m

Tension in the spring:

T = k x = 7.5 \times 0.1 = 0.75

JEE Main · 2023 · 06 Apr 2023 · Shift 1 · Single correct option

Practise more: all JEE Main PYQs on Laws of Motion →

More JEE Main questions on Laws of Motion

A simple pendulum has a bob with mass $m$ and charge q . The pendulum string has negligible mass. When a uniform and horizontal electric field $E$ is applied, the tension in the string changes. The final tension in the string, when pendulum attains an equilibrium positi …
JEE Main 2026View solution →
A large drum having radius R is spinning around its axis with angular velocity $ω$ , as shown in figure. The minimum value of $ω$ so that a body of mass M remains stuck to the inner wall of the drum, taking the coefficient of friction between the drum surface and mas …
JEE Main 2026View solution →
A spring of force constant $15 N / m$ is cut into two pieces. If the ratio of their length is $1 : 3$ , then the force constant of smaller piece is ______ $N / m$
JEE Main 2026View solution →
In the given figure the blocks A, B and C weigh 4 kg, 6 kg and 8 kg respectively. The co-efficient of sliding friction between any two surfaces is 0.5. The force $F$ required to slide the block C with constant speed is ______ N. (Used …
JEE Main 2026View solution →
A block of mass 5 kg is moving on an inclined plane which makes an angle of $3 0^{\circ}$ with the horizontal. Friction coefficient between the block and inclined plane surface is $\frac{3}{2}$ . The force to be applied on the block so that the block will move down witho …
JEE Main 2026View solution →
A particle of mass m falls from rest through a resistive medium having resistive force, $F = - kv$ , where v is the velocity of the particle and k is a constant. Which of the following graphs represents velocity (v) versus time(t)?
JEE Main 2026View solution →