A box of mass \(15\) kg is kept on the floor of a stationary trolley. The coefficient of static friction between the box and the trolley is \(0.12\cdot\) Keeping the box in a stationary state over the trolley; the maximum acceleration with which the trolley can be moved horizontally in \(\text{ms}^{-2}\) is: (\(g=10\) \(\text{ms}^{-2}\))
1. \(1.5\)
2. \(1.8\)
3. \(2.1\)
4. \(1.2\)
Subtopic:  Friction |
 63%
Level 2: 60%+
NEET - 2026
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There are two inclined surfaces of equal length \((L)\) and same angle of inclination \(45^\circ\) with the horizontal. One of them is rough and the other is perfectly smooth. A given body takes \(2\) times as much time to slide down on rough surface than on the smooth surface. The coefficient of kinetic friction \((\mu_k)\) between the object and the rough surface is close to:
1. \(0.5\) 2. \(0.75\)
3. \(0.25\) 4. \(0.40\)
Subtopic:  Friction |
 51%
Level 3: 35%-60%
NEET - 2025
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Calculate the maximum acceleration of a moving car so that a body lying on the floor of the car remains stationary. The coefficient of static friction between the body and the floor is \(0.15\). (take \(g=10\) ms–2)
1. \(50\) ms–2 2. \(1.2\) ms–2
3. \(150\) ms–2 4. \(1.5\) ms–2
Subtopic:  Friction |
 83%
Level 1: 80%+
NEET - 2023
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A block of mass \(2\) kg is placed on inclined rough surface \(AC\) (as shown in the figure) of coefficient of friction \(\mu.\) If \(g=10\) ms–1, the net force (in N) on the block will be:
                    
1. \(10\sqrt3\)
2. zero
3. \(10\)
4. \(20\)
Subtopic:  Friction |
 67%
Level 2: 60%+
NEET - 2023
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Calculate the acceleration of the block and trolly system shown in the figure. The coefficient of kinetic friction between the trolly and the surface is \(0.05.\) 
\(g=10~\text{m/s}^2,\) the mass of the string is negligible and no other friction exists)

1. \( 1.25~\text{m/s}^2\) 2. \( 1.50~\text{m/s}^2\)
3. \(1.66~\text{m/s}^2\) 4. \( 1.00~\text{m/s}^2\)
Subtopic:  Friction |
 67%
Level 2: 60%+
NEET - 2020
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A body of mass \(m\) is kept on a rough horizontal surface (coefficient of friction = \(\mu).\) A horizontal force is applied to the body, but it does not move. The resultant of normal reaction and the frictional force acting on the object is given by \(\vec {F}\) where:
1. \(|{\vec {F}}| = mg+\mu mg\)
2. \(|\vec {F}| =\mu mg\)
3. \(|\vec {F}| \le mg\sqrt{1+\mu^2}\)
4. \(|\vec{F}| = mg\)

Subtopic:  Friction |
 75%
Level 2: 60%+
NEET - 2019
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Which one of the following statements is incorrect?

1. Rolling friction is smaller than sliding friction.
2. The limiting value of static friction is directly proportional to the normal reaction.
3. Frictional force opposes the relative motion.
4. The coefficient of sliding friction has dimensions of length.
Subtopic:  Friction |
 79%
Level 2: 60%+
NEET - 2018
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A plank with a box on it at one end is gradually raised about the other end. As the angle of inclination with the horizontal reaches \(30^\circ,\) the box starts to slip and slide \(4.0~\text m\) down the plank in \(4.0~\text s.\) The coefficients of static and kinetic friction between the box and the plank will be, respectively:

1. \(0.6\) and \(0.6\)  2. \(0.6\) and \(0.5\) 
3. \(0.5\) and \(0.6\)  4. \(0.4\) and \(0.3\)
Subtopic:  Friction |
 71%
Level 2: 60%+
NEET - 2015
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A block \(\mathrm{A}\) of mass \(m_1\) rests on a horizontal table. A light string connected to it passes over a frictionless pulley at the edge of the table and from its other end, another block \(\mathrm{B}\) of mass \(m_2\) is suspended. The coefficient of kinetic friction between block \(\mathrm{A}\) and the table is \(\mu_k\). When block \(\mathrm{A}\) is sliding on the table, the tension in the string is:

1. \( \dfrac{\left({m}_2+\mu_{{k}}{m}_1\right) {g}}{\left({m}_1+{m}_2\right)}\) 2. \( \dfrac{\left({m}_2-\mu_{{k}} {m}_1\right) {g}}{\left({m}_1+{m}_2\right)}\)
3. \(\dfrac{{m}_1 {~m}_2\left(1-\mu_{{k}}\right) {g}}{\left({m}_1+{m}_2\right)}\) 4. \( \dfrac{{m}_1 {~m}_2\left(1+\mu_{{k}}\right)}{{m}_1+{m}_2} {g}\)
Subtopic:  Friction |
 53%
Level 3: 35%-60%
NEET - 2015
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A system consists of three masses \(m_1,\) \(m_2,\) and \(m_3\) connected by a string passing over a pulley \(\mathrm{P}.\) The mass \(m_1\) hangs freely, and \(m_2\) and \(m_3\) are on a rough horizontal table (the coefficient of friction \(=\mu.\)) The pulley is frictionless and of negligible mass. The downward acceleration of mass \(m_1\) is:
(Assume \(m_1=m_2=m_3=m\) and \(g\) is the acceleration due to gravity.)

1. \(\dfrac{g(1-g \mu)}{9}\) 2. \(\dfrac{2 g \mu}{3}\)
3. \( \dfrac{g(1-2 \mu)}{3}\) 4. \(\dfrac{g(1-2 \mu)}{2}\)
Subtopic:  Friction |
 85%
Level 1: 80%+
AIPMT - 2014
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