The blocks A and B are arranged as shown in the figure. The pulley is frictionless. The mass of A is 10 kg. The coefficient of friction of A with the horizontal surface is 0.20. The minimum mass of B to start the motion will be 

(1) 2 kg

(2) 0.2 kg

(3) 5 kg

(4) 10 kg

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 

(1) 32 m

(2) 24 m

(3) 16 m

(4) 12 m

Assuming the coefficient of friction between the road and tyres of a car to be 0.5, the maximum speed with which the car can move round a curve of 40.0 m radius without slipping, if the road is unbanked, should be 

(1) 25 m/s

(2) 19 m/s

(3) 14 m/s

(4) 11 m/s

Consider a car moving on a straight road with a speed of 100 m/s. The distance at which the car can be stopped is: $[{\mu }_k=0.5]$ 

(1) 100 m

(2) 400 m

(3) 800 m

(4) 1000 m

A block of mass 0.1 kg is held against a wall by applying a horizontal force of 5 N on the block. If the coefficient of friction between the block and the wall is 0.5, the magnitude of the frictional force acting on the block is 

(1) 2.5 N

(2) 0.98 N

(3) 4.9 N

(4) 0.49 N

A body of mass m rests on horizontal surface. The coefficient of friction between the body and the surface is μ. If the mass is pulled by a force P as shown in the figure, the limiting friction between body and surface will be 

(1) μmg

(2) $\mu \left[mg+\left(\frac{{\displaystyle P}}{{\displaystyle 2}}\right)\right]$

(3) $\mu \left[mg-\left(\frac{{\displaystyle P}}{{\displaystyle 2}}\right)\right]$

(4) $\mu \left[mg-\left(\frac{{\displaystyle \sqrt{3}P}}{{\displaystyle 2}}\right)\right]$

Two blocks A and B of masses 3m and m respectively are connected by a massless and inextenisible 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. $g,\frac{g}{3}$

2. $\frac{g}{3},g$

3. $g,g$

4. $\frac{g}{3},\frac{g}{3}$

A spring of force constant k is cut into lengths of ratio 1:2:3. They are connected in series and the new force constant is $k^{\text{'}}$. If they are connected in parallel and force constant is $k^{\text{'}\text{'}}, then k^{\text{'}}:k^{\text{'}\text{'}}$ is 

(1) 1:6

(2) 1:9

(3) 1:11

(4) 6:11

Three blocks A, B and C of masses 4 kg, 2 kg and 1 kg respectively, are in contact on a frictionless surface, as shown. If a force of 14 N is applied on the 4 kg block, then the contact force between A and B is


1.2N

2. 6N

3. 8N

4. 18N

A block A of mass m₁ rests on a horizontal table. A light string connected to it passes over a frictionless pulley at the edge of table and from its other end another block B of mass m₂ is suspended. The coefficient of kinetic friction between the block and the table is  μ_k. When the block A is sliding on the table, the tension in the string is

1. (m₂+μ_km₁)g /(m₁+m₂)

2. (m₂-μ_km₁)g/(m₁+m₂)

3. m₁m₂(1+μ_k)g/(m₁+m₂)

4. m₁m₂(1-μ_k)g/(m₁+m₂)