Total Questions:25 Total Time: 45 Min
Remaining:
Question:A force of 98 N is required to just start moving a body of mass 100 kg over ice. The coefficient of static friction is
0.6
0.4
0.2
0.1
Question:A block weighs W is held against a vertical wall by applying a horizontal force F. The minimum value of F needed to hold the block is
Less than W
Equal to W
Greater than W
Data is insufficient
Question:The maximum static frictional force is
Equal to twice the area of surface in contact
Independent of the area of surface in contact
Equal to the area of surface in contact
None of the above
Question:Maximum value of static friction is called
Limiting friction
Rolling friction
Normal reaction
Coefficient of friction
Question:Pulling force making an angle \(\theta \) to the horizontal is applied on a block of weight W placed on a horizontal table. If the angle of friction is \(\alpha \), then the magnitude of force required to move the body is equal to
\(\frac{{W\sin \alpha }}{{g\tan (\theta - \alpha )}}\)
\(\frac{{W\cos \alpha }}{{\cos (\theta - \alpha )}}\)
\(\frac{{W\sin \alpha }}{{\cos (\theta - \alpha )}}\)
\(\frac{{W\tan \alpha }}{{\sin (\theta - \alpha )}}\)
Question:When two surfaces are coated with a lubricant, then they
Stick to each other
Slide upon each other
Roll upon each other
None of these
Question: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
0.38
0.44
0.52
Question: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
900 N
100 N
1100 N
1200 N
Question:To avoid slipping while walking on ice, one should take smaller steps because of the
Friction of ice is large
Larger normal reaction
Friction of ice is small
Smaller normal reaction
Question: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 \(\mu \), is
\(\mu Rg\)
\(Rg\sqrt \mu \)
\(\mu \sqrt {Rg} \)
\(\sqrt {\mu Rg} \)
Question:A car is moving along a straight horizontal road with a speed \({v_0}\). If the coefficient of friction between the tyres and the road is \(\mu \), the shortest distance in which the car can be stopped is
\(\frac{{v_0^2}}{{2\mu g}}\)
\(\frac{{{v_0}}}{{\mu g}}\)
\({\left( {\frac{{{v_0}}}{{\mu g}}} \right)^2}\)
\(\frac{{{v_0}}}{\mu }\)
Question:A block of mass 5 kg is on a rough horizontal surface and is at rest. Now a force of 24 N is imparted to it with negligible impulse. If the coefficient of kinetic friction is 0.4 and \(g = 9.8\,m/{s^2}\), then the acceleration of the block is
\(0.26\,m/{s^2}\)
\(0.39\,m/{s^2}\)
\(0.69\,m/{s^2}\)
\(0.88\,m/{s^2}\)
Question:A body of mass 2 kg is being dragged with uniform velocity of 2 m/s on a rough horizontal plane. The coefficient of friction between the body and the surface is 0.20. The amount of heat generated in 5 sec is \((J = 4.2\,joule/cal\) and \(g = 9.8\,m/{s^2})\)
9.33 cal
10.21 cal
12.67 cal
13.34 cal
Question:A block of mass 50 kg slides over a horizontal distance of 1 m. If the coefficient of friction between their surfaces is 0.2, then work done against friction is
98 J
72J
56 J
34 J
Question:On the horizontal surface of a truck (\(\mu \) = 0.6), a block of mass 1 kg is placed. If the truck is accelerating at the rate of 5m/sec\(^{\rm{2}}\) then frictional force on the block will be
5 N
6 N
5.88 N
8 N
Question:A vehicle of mass m is moving on a rough horizontal road with momentum P. If the coefficient of friction between the tyres and the road be \(\mu \), then the stopping distance is
\(\frac{P}{{2\mu \,m\,g}}\)
\(\frac{{{P^2}}}{{2\mu \,m\,g}}\)
\(\frac{P}{{2\mu \,m{\,^2}g}}\)
\(\frac{{{P^2}}}{{2\mu \,m{\,^2}g}}\)
Question:A body of weight 64 N is pushed with just enough force to start it moving across a horizontal floor and the same force continues to act afterwards. If the coefficients of static and dynamic friction are 0.6 and 0.4 respectively, the acceleration of the body will be (Acceleration due to gravity = g)
\(\frac{g}{{6.4}}\)
0.64 g
\(\frac{g}{{32}}\)
0.2 g
Question:A body is moving along a rough horizontal surface with an initial velocity \(6\,\,m/s.\) If the body comes to rest after travelling 9 m, then the coefficient of sliding friction will be
0.8
Question:Consider a car moving on a straight road with a speed of 100 m/s. The distance at which car can be stopped is \([{\mu _k} = 0.5]\)
100 m
400 m
800 m
1000 m
Question:A cylinder of 10 kg is sliding in a plane with an initial velocity of 10 m/s. If the coefficient of friction between the surface and cylinder is 0.5 then before stopping, it will cover. \((g = 10\,\,m/{s^2})\)
2.5 m
5 m
7.5 m
10 m
Question:When a body is lying on a rough inclined plane and does not move, the force of friction
is equal to \(\mu R\)
is less than \(\mu R\)
is greater than \(\mu R\)
is equal to R
Question:The upper half of an inclined plane of inclination q is perfectly smooth while the lower half is rough. A body starting from the rest at top comes back to rest at the bottom if the coefficient of friction for the lower half is given by
\(\mu \) = sin \(\theta \)
\(\mu \) = cot \(\theta \)
\(\mu \) = 2 cos \(\theta \)
\(\mu \)= 2 tan \(\theta \)
Question:A body is sliding down an inclined plane having coefficient of friction 0.5. If the normal reaction is twice that of the resultant downward force along the incline, the angle between the inclined plane and the horizontal is [EAMCET (Engg.) 2000]
15\(^0\)
30 \(^0\)
45 \(^0\)
60 \(^0\)
Question:A body of mass 10 kg is lying on a rough plane inclined at an angle of 30\(^0\) to the horizontal and the coefficient of friction is 0.5. the minimum force required to pull the body up the plane is
914 N
91.4 N
9.14 N
0.914 N
Question:A block of mass 1 kg slides down on a rough inclined plane of inclination 60\(^0\) starting from its top. If the coefficient of kinetic friction is 0.5 and length of the plane is 1 m, then work done against friction is (Take g = 9.8 m/s\(^2\))
9.82 J
4.94 J
2.45J
1.96 J