Pulley

Q. A solid cylinder of radius R is kept at rest on a smooth horizontal surface. A horizontal force is applied to move the cylinder under pure rolling. Then height of force from horizontal surface is does smooth and rough surface change the height for pure rolling to happen??

Q. The acceleration of the system of two bodies over the wedge as shown in the figure is

1. $1{m/s}^2$
2. $2{m/s}^2$
3. $0.5{m/s}^2$
4. $10{m/s}^2$

Q.

Swimming is possible on account of

1. First law of motion

2. Second law of motion

3. Third law of motion

4. Newton's law of gravitation

Q.

The principle used in swimming is Newtons third law of motion.

1. True
2. False

Q. As shown in figure, a man of mass $M$ is standing on a platform and holding an inextensible massless string which passes over a system of ideal pulleys. Another body of mass $m$ is hanging as shown in figure. Find the force exerted by the platform on man if $M=50\text{kg},m=10\text{kg}$, Take $g=10{\text{m/s}}^2$.

1. $10\text{N}$
2. $100\text{N}$
3. $25\text{N}$
4. $50\text{N}$

Q.

How does a swimmer moves forward in water?

Q.

If action and reaction are always equal and opposite, why dont they always cancel one another and leave no net force for accelerating a body?

Q.

Swimming is based on the principle of:

1. Newton’‘s 1st law

2. Newton‘s 2nd law

3. Newton’s 3rd law

4. None

Q. 39. If m1=10kg;m2=4kg;m3:2kg, the acceleration of the system is ?

Q. Find the tension in the string between the pulleys and the acceleration of the blocks as shown in the figure. Assume that there is no slipping between the string and the pulleys.
[Given, mass of bigger pulley $=2m$, radius of bigger pulley $=R$, mass of smaller pulley $=m$ and radius of smaller pulley $=\frac{R}{2}$]

1. $\frac{4}{3}mg,\frac{2g}{9}$
2. $\frac{9}{4}mg,\frac{9}{2}g$
3. $mg,g$
4. $mg,\frac{g}{2}$

Q.

In the arrangement of three blocks as shown in figure, the string is inextensible. If the directions of accelerations are as shown in the figure, then determine the constraint relation.

1. 

2. 

3. 

4. None of these

Q. What is central force in easy words?

Q. a disc of radius 2m and mass 100kg on a horizontal floor its centre of mass has speed of 20 how much work is need to stop i

Q.

A stick is thrown in the air and lands on the ground at same distance from the thrower. The centre of mass of the stick will move along a parabolic path

1. only if the stick has a shape such that its centre of mass is located at same point on it and not outside

2. in all cases

3. only if the stick has linear motion but no rotational motion

4. only if the stick is uniform

Q. Two blocks $m_1=5\text{gm}$ and $m_2=10\text{gm}$ are hung vertically over a light frictionless pulley as shown here. What is the acceleration of the masses when they are left free?

(where $g$ is acceleration due to gravity)

1. $\frac{g}{3}$
2. $\frac{g}{2}$
3. $g$
4. $\frac{g}{5}$

Q.

Top view of a block on a table is shown (g = 10 $m/s^2$). Find out the acceleration of the block, when friction is present. M = 10 kg

1. 0 m

2. 4 - 5 m

3. 1 m

4. (5 - 4) m

Q. In a closed organ pipe of length 105 cm, standingwaves are set up corresponding to third overtone.What distance from the closed end, a pressurenode is formed?(2) 15 cm(1) 5 cm(3) 25 cm(4) 30 cm

Q.

Why does a swimmer moves his hands backward while swimming in water?

Q. Immediately on cutting the taut string, the acceleration of one of the blocks is found to be $2m{s}^{-2}.$ If $m_1=6kg,m_2$ is equal to $(g=10m{s}^{-2})$

1. $4kg$
2. $5kg$
3. $2kg$
4. $8kg$

Q.

Swimming can be explained by

1. Newtons law of gravitation

2. First law of motion

3. Second law of motion

4. Third law of motion

Q. In the following arrangement, the system is initially at rest. The $5\text{kg}$ block is now released. Assuming the pulleys and string to be massless and smooth, the acceleration of blocks are

1. $a_A=\frac{g}{7}m/s^2$
2. $a_B=0m/s^2$
3. $a_c=\frac{g}{14}m/s^2$
4. $2a_C=a_A$

Q. 64.A spring of force constant k is cut into three equal pieces. If these pieces are connected in parallel the force constant of the combination will Be :??

Q. rod has radius of 200 mm and length of 20 cm. A 200 N force compresses along its length. Calculate the stress developed in the rod. Options: 1.62 × 103 Pa Wrong 2 × 102 Pa Should have chosen 1.5 × 103 Pa 1.27 Pa

Q.

The relation between the magnitudes of acceleration of pulley $P_1$ ($a_{p_1}$) and that of pulley $P_3$ ($a_{p_3}$) is

1. =

2. =

3. =

4. =

Q.

“Action and reaction are equal and opposite, still their resultant is not zero.” Explain.

Q. Seven pulleys are connected with the help of three light strings as shown in the figure given below. Consider $P_3,P_4$ and $P_5$ as light pulleys and pulleys $P_6$ and $P_7$ have masses $m$ each. For this arrangement mark the correct statement(s).

1. Tension in the string connecting $P_1,P_3$ and $P_4$ is zero.
2. Tension in the string connecting $P_1,P_3$ and $P_4$ is $mg/3$ .
3. Tension in all the 3 strings is same and equal to zero.
4. Acceleration of $P_6$ is $g$ downward and that of $P_7$ is $g$ upward.

Q. Find the acceleration of the blocks A and B in the three situations shown in figure (5−E17).

Figure

Q. Let m₁ = 1 kg, m₂ = 2 kg and m₃ = 3 kg in figure (5−E12). Find the accelerations of m₁, m₂ and m₃. The string from the upper pulley to m₁ is 20 cm when the system is released from rest. How long will it take before m₁ strikes the pulley?

Figure

Q. For the figure, both the pulleys are massless and frictionless. The right side pully can move. A force F, of any possible magnitude, is applied in horizontal direction. There is no friction between M and ground.
${\mu }_{1}and{\mu }_2$ are the coefficients of friction between the blocks as shown. Column I gives the different relations between ${\mu }_{1}and{\mu }_2$, and Column II is regarding the motion of M. Match the columns


$\begin{array}{cccc}& \text{Column I}& & \text{Column II}\\ \text{i.}& \text{If}\mu 1=\mu 2=0& \text{a.}& \text{May accelerate towards right}\\ \text{ii.}& \text{If}\mu 1=\mu 2\ne 0& \text{b.}& \text{May accelerate towards left}\\ \text{iii.}& \text{If}\mu 1>\mu 2& \text{c.}& \text{Does not accelerate}\\ \text{iv.}& \text{If}\mu 1<\mu 2& \text{d.}& \text{May or may not accelerate}\end{array}$

1. i - c; ii - c; iii - b, d; iv - a
2. i - c; ii - c; iii - b, d; iv - a, d
3. i - c; ii - c; iii - b; iv - a, d
4. i - c; ii - d, iii - b, d; iv - a, d

Q. In the pulley system shown in figure the movable pulleys $A,B$ and $C$ are of mass $1\text{kg}$ each. $D$ and $E$ are fixed pulleys. The strings are light and inextensible. Choose the correct alternative(s). All pulleys are frictionless.

1. Tension in the string is $6.5\text{N}$
2. Acceleration of pulley $A$ is $g/3$ downward
3. Acceleration of pulley $B$ is $g/6$ upward
4. Acceleration of pulley $C$ is $g/3$ upward