Physics - Laws Motion - Quiz-5

A block of mass 4 kg is suspended through two light spring balances A and B. Then A and B will read respectively

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4 kg and zero kg
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Zero kg and 4 kg
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4 kg and 4 kg
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2 kg and 2 kg

Two masses M and M/2 are joint together by means of a light inextensible string passes over a frictionless pulley as shown in figure. When bigger mass is released the small one will ascend with an acceleration of

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g/3
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3g/2
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g/2
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g

Two masses m₁ and m₂ (m₁ > m₂) are connected by massless flexible and inextensible string passed over massless and frictionless pulley. The acceleration of centre of mass is

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${(\frac{m_{1} - m_{2}}{m_{1} + m_{2}})}^{2} g$
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$\frac{m_{1} - m_{2}}{m_{1} + m_{2}} g$
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$\frac{m_{1} + m_{2}}{m_{1} - m_{2}} g$
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Zero

The mass of a body measured by a physical balance in a lift at rest is found to be m. If the lift is going up with an acceleration a, its mass will be measured as:

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$m (1 - \frac{a}{g})$
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$m (1 + \frac{a}{g})$
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m
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Zero

Three weights W, 2W and 3W are connected to identical springs suspended from a rigid horizontal rod. The assembly of the rod and the weights fall freely. The positions of the weights from the rod are such that

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3W will be farthest
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W will be farthest
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All will be at the same distance
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2W will be farthest

When forces F₁, F₂, F₃ are acting on a particle of mass m such that F₂ and F₃ are mutually perpendicular, then the particle remains stationary. If the force F₁ is now removed then the acceleration of the particle is

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$F_{1} / m$
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$F_{2} F_{3} / m F_{1}$
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$(F_{2} - F_{3}) / m$
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$F_{2} / m$

A false balance has equal arms. An object weighs X when placed in one pan and Y when placed in other pan, then the weight W of the object is equal to

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$\sqrt{X Y}$
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$\frac{X + Y}{2}$
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$\frac{X^{2} + Y^{2}}{2}$
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$\frac{2}{\sqrt{X^{2} + Y^{2}}}$

The pulleys and strings shown in the figure are smooth and of negligible mass. For the system to remain in equilibrium, the angle θ should be:

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0°
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30°
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45°
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60°

A string of negligible mass going over a clamped pulley of mass m supports a block of mass M as shown in the figure. The force on the pulley by the clamp is given by:

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$\sqrt{2} M g$
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$\sqrt{2} m g$
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$\sqrt{{(M + m)}^{2} + m^{2}} g$
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$\sqrt{{(M + m)}^{2} + M^{2}} g$

A pulley fixed to the ceilling carries a string with blocks of mass m and 3 m attached to its ends. The masses of string and pulley are negligible. When the system is released, its centre of mass moves with what acceleration

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0
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g/4
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g/2
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–g/2

A block B is placed on top of block A. The mass of block B is less than the mass of block A. Friction exists between the blocks, whereas the ground on which block A is placed is assumed to be smooth. A horizontal force F, increasing linearly with time begins to act on B. The acceleration a_A and a_B of blocks A and B respectively are plotted against t. The correctly plotted graph is:

The force-time (F – t) curve of a particle executing linear motion is as shown in the figure. The momentum acquired by the particle in time interval from zero to 8 second will be

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– 2 N-s
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+ 4 N-s
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6 N-s
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Zero

A body of 2 kg has an initial speed 5ms^–1. A force acts on it for some time in the direction of motion. The force time graph is shown in figure. The final speed of the body.

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9.25 ms^–1
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5 ms^–1
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14.25 ms^–1
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4.25 ms^–1

A particle of mass m, initially at rest, is acted upon by a variable force F for a brief interval of time T. It begins to move with a velocity u after the force stops acting. F is shown in the graph as a function of time. The curve is an ellipse.

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$u = \frac{π F_{0}^{2}}{2 m}$
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$u = \frac{π T^{2}}{8 m}$
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$u = \frac{π F_{0} T}{4 m}$
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$u = \frac{F_{0} T}{2 m}$

A body of mass 3kg is acted upon by a force which varies as shown in the graph below. The momentum acquired is given by

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Zero
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5 N-s
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30 N-s
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50 N-s

The variation of momentum with the time of one of the bodies in a two-body collision is shown in fig. The instantaneous force is the maximum corresponding to the point-

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P
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Q
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R
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S

Figures I, II, III and IV depict variation of force with time.

(I)
(II)
(III)
(IV)

The impulse is highest in the case of situations depicted. Figure

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I and II
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III and I
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III and IV
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IV only

The masses of 10 kg and 20 kg respectively are connected by a massless spring as shown in figure. A force of 200 N acts on the 20 kg mass. At the instant shown, the 10 kg mass has acceleration 12 m/sec². What is the acceleration of 20 kg mass?

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12 m/sec²
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4 m/sec²
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10 m/sec²
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Zero

Two masses M and m are connected by a weightless string. They are pulled by a force F on a frictionless horizontal surface. The tension in the string will be

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$\frac{F M}{m + M}$
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$\frac{F}{M + m}$
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$\frac{F M}{m}$
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$\frac{F m}{M + m}$

A uniform rope of length l lies on a table. If the coefficient of friction is μ, then the maximum length l₁ of the part of this rope which can overhang from the edge of the table without sliding down is

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$\frac{l}{μ}$
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$\frac{l}{μ + l}$
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$\frac{μ l}{1 + μ}$
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$\frac{μ l}{μ - 1}$

A heavy uniform chain lies on a horizontal table-top. If the coefficient of friction between the chain and table surface is 0.25, then the maximum fraction of length of the chain, that can hang over one edge of the table is

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20%
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25%
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35%
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15%

A uniform chain of length L hangs partly from a table which is kept in equilibrium by friction. If the maximum length that can be supported without slipping is l, then the coefficient of friction between the table and the chain is:

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$\frac{l}{L}$
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$\frac{l}{L + l}$
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$\frac{l}{L - l}$
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$\frac{L}{L + l}$

When two surfaces are coated with a lubricant, then they

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Stick to each other
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Slide upon each other
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Roll upon each other
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None of these

A 20 kg block is initially at rest on a rough horizontal surface. A horizontal force of 75 N is required to set the block in motion. After it is in motion, a horizontal force of 60 N is required to keep the block moving with constant speed. The coefficient of static friction is

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0.38
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0.44
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0.52
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0.60

A block A with mass 100 kg is resting on another block B of mass 200 kg. As shown in figure a horizontal rope tied to a wall holds it. The coefficient of friction between A and B is 0.2 while coefficient of friction between B and the ground is 0.3. The minimum required force F to start moving B will be

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900 N
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100 N
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1100 N
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1200 N

A horizontal force of 10 N is necessary to just hold a block stationary against a wall. The coefficient of friction between the block and the wall is 0.2. The weight of the block is

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2 N
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20 N
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50 N
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100 N

The coefficient of static friction, μ_s, between block A of mass 2 kg and the table as shown in the figure is 0.2. What would be the maximum mass value of block B so that the two blocks do not move? The string and the pulley are assumed to be smooth and massless. (g = 10 m/s²)

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2.0 kg
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4.0 kg
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0.2 kg
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0.4 kg

The maximum speed that can be achieved without skidding by a car on a circular unbanked road of radius R and coefficient of static friction μ, is

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$μ R g$
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$R g \sqrt{μ}$
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$μ \sqrt{R g}$
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$\sqrt{μ R g}$

Two carts of masses 200 kg and 300 kg on horizontal rails are pushed apart. Suppose the coefficient of friction between the carts and the rails are same. If the 200 kg cart travels a distance of 36 m and stops, then the distance travelled by the cart weighing 300 kg is

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32 m
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24 m
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16 m
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12 m

A block of mass 50 kg can slide on a rough horizontal surface. The coefficient of friction between the block and the surface is 0.6. The least force of pull acting at an angle of 30° to the upward drawn vertical which causes the block to just slide is

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29.43 N
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219.6 N
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21.96 N
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294.3 N

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Practice Physics Quiz Questions and Answers

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Practice Physics Quiz Questions and Answers

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