Spring Force

Q. 110.What is the order of mass of a human?

Q.

What is the dimension of k/m where k is the force constant and m is the mass of the oscillating object?

1. [T^-2]

2. [T²]

3. [T¹]

4. [T^-1]

Q. 29. Three blocks are placed as shown in figure. Mass of A, Band C are m, , m, and m, respectively. The force eerteby block C on B isABn(2) (m, + m2lg(1) m, g(4) (m, m2+mg(3) mg

Q. A uniform rod of mass m and length l is kept on a smooth horizontal surface. An impulse p is applied to the one end B perpendicular to the length of the rod. What is the time taken by the rod to turn through right angle?

Q. What is the percentage increase in the length of a wire of diameter 2.5 mm, stretched by a force of 100 kg wt?

Q.

Figure below shows a light spring balance connected to two blocks of mass 20 kg each. The graduations in the balance measure the tension in the spring. What is the reading of the balance?

1. 400N

2. 0N

3. 200N

4. 100N

Q. a block ofmass M is attached to a horizontal spring with spring cons†an t k is moving with SHM having amplitude A1. at an ins†an t when the block passes through its equilbrium position a lump of putty of mass m is dropped vertically on the block from a very small height and sticks to it find : 1. new amplitude and period 2. new amplitude when lump of putty is dropped on the block when it is at an end on of its path

Q. A force of 6.4 N stretches a vertical spring by 0.1 m. The mass that must be suspended from the spring so that it oscillates with a period of pi/4 sec is how much

Q.

What is the impulsive force?

Q. 77. Four point of masses 3kg, 2kg, 1kg, & 4kg are placed at the corner of a square of side 2m.Find the centre of mass of the system w.r.t. the centre of square

Q. In the figure a smooth pulley of negligible weight is suspended by a spring balance. Weights of $1\text{kg}$ and $5\text{kg}$ are attached to the opposite ends of a string passing over the pulley and move with acceleration because of gravity. During the motion, the spring balance reads a weight of

1. $6\text{kg}$
2. Less than $6\text{kg}$
3. More than $6\text{kg}$
4. May be more or less than $6\text{kg}$

Q. A boy and a cart are moving in the same direction, with the boy going twice as fast as the cart. When he gets into the cart, the speed of the cart increases by 20%. Find the ratio of mass of cart to the mass of boy?

Q. Mass M is divided into two parts m1 and m2.For a given seperation the ratio of m1/M for which the gravitational attraction between the two parts becomes maximum is:-

Q. Two blocks A and B of masses $3m$ and $m$ respectively are connected by a massless and inextensible string. The whole system is suspended by a massless spring as shown in figure. The magnitudes of acceleration of A and B immediately after the string is cut, are respectively

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

Q. Find the reading of the spring balance if it is assumed to be of negligible mass.
(Take $g=10m/s^2$)

1. $3kg$
2. $2.4kg$
3. $2kg$
4. $2.5kg$

Q. Find the reading of the spring balance for the figure shown. Take $g=10m/s^2$

1. $1.2kg$
2. $2.4kg$
3. $3.6kg$
4. $4.8kg$

Q.

A metal block of density $6000kg{m}^{-3}$ and mass $1.2kg$ is suspended through a spring of spring constant $200N{m}^{-1}$. The spring-block system is dipped in water kept in a vessel. The water has a mass of $260g$ and the block is at a height $40cm$ above the bottom of the vessel. If the support to the spring is broken, what will be the rise in the temperature of the water? Specific heat capacity of the block is $250Jk{g}^{-1}{K}^{-1}$ and that of water is $4200Jk{g}^{-1}{K}^{-1}$. Heat capacities of the vessel and the spring are negligible.

1. 

2. 

3. 

4. 

Q. As shown in the figure, two equal masses each of 2 kg are suspended from a spring balance. The reading of the spring balance will be

1. Zero
2. 2 kg
3. 4 kg
4. Between zero and 2 kg

Q. A block $\left(B\right)$ is attached to two unstretched springs $S_1$ and $S_2$ with spring constant $2k$ and $4k$ respectively. The other ends are attached to two supports $m_1$ and $m_2$ not attached to the walls. The springs and supports have negligible mass and the surface is frictionless. The block $B$ is displaced towards wall $1$ by a small distance $x$ and released. The block returns and moves a maximum distance $y$ towards wall $2$. Displacement $x$ and $y$ is measured with respect to the equilibrium position of the block $B$. The ratio of $\frac{y}{x}$ is

1. $\frac{1}{2}$
2. $2$
3. $\sqrt{2}$
4. $\frac{1}{\sqrt{2}}$

Q. 35.A cricket bat is cut at the location of its centre of mass as shown then (a) two pieces will have same mass (b) bottom piece will have larger mass (c)handle piece will have larger mass (d) mass of handle piece is double the mass of bottom piece

Q. A bus is moving on a circrcular track whose radius is 400m with a speed of 72km/hr . A spring balance is fixed on the roof of the bus and a block of 5 kg is hanged on it. What will be the reading of the spring balance when the bus is moving in the circle.

Q. A block $m_2$ is loaded onto another block $m_1$ placed on a spring of stiffness $k$ as shown in the figure. If block $m_2$ is suddenly removed, then magnitude of acceleration of block $m_1$ just after the removal of $m_2$ will be:

1. $\frac{\sqrt{m_1{m}_2}}{m_1+m_{2}g}$
2. $\left(\frac{m_2}{m_1}g\right)$
3. $\left(\frac{m_1}{m_2}g\right)$
4. $\frac{m_1+m_2}{m_1-m_2}$

Q. What is the reading of spring balance $D$ ?
(All the springs are ideal and identical)

1. $\frac{mg}{4}$
2. $2mg$
3. $\frac{mg}{2}$
4. $mg$

Q.

Match the block diagrams of block of mass m, with their corresponding free body diagram. (spring consent is kand x is change in spring length).

1. p-(i); q-(i); r-(iii); s-(vi)

2. p-(ii); q-(i); r-(iii); s-(vi)

3. p-(i); q-(ii); r-(iii); s-(vi)

4. p-(i); q-(i); r-(iv); s-(v)

Q. As shown in the figure, the $2\text{kg}$ block is subjected to an external force of $42\text{N}$. What is the value of normal reaction ($N$) acting on the $3\text{kg}$ block (exerted on it by the surface), when spring reaches maximum extension? (Take $g=10{\text{m/s}}^2$)

1. $20\text{N}$
2. $30\text{N}$
3. $8\text{N}$
4. $5\text{N}$

Q. 35.A batsman deflect a ball by right angle without changing its initial speed which is equal to 54 KMPH. What is the impluse imparted to the ball? ( Mass of ball0.15 kg)

Q. A rod of length is 3 m and its mass acting per unit-lenght is directly proportional to distance x fronmone of its end then its centre of gravity from thatend will be at.(A) 1.5 m(B) 2 m(D) 3.0 m (C.B.S.E. 2002)(C) 2.5 mm

Q.

The forces acting on the blocks are shown. What is the displacement of centre of mass in time t? The initial velocity of each is zero.

1. $\frac{F_o{t}^2}{2m}$

2. $\frac{F_o{t}^2}{6m}$

3. $\frac{F_o{t}^2}{3m}$

4. $\frac{F_o{t}^2}{6m}$

Q.

As shown in Fig.7.40, the two sides of a step ladder BA and CA are 1.6 m long and hinged at A. A rope DE, 0.5 m is tied half way up. A weight 40 kg is suspended from a point F, 1.2 m from B along the ladder BA. Assuming the floor to be frictionless and neglecting the weight of the ladder, find the tension in the rope and forces exerted by the floor on the ladder. (Take g = 9.8 m/s²)

(Hint: Consider the equilibrium of each side of the ladder separately.)

Q. What is the equivalent spring constant for the syatem shown below in the figure?
(All the springs are ideal and identical having spring constant $k\text{N/m}$)

1. $\frac{6k}{7}$
2. $\frac{3k}{5}$
3. $\frac{2k}{5}$
4. $2k$