Direction of Friction
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- 5 kg
- 20 kg
- 2 kg
- 0.5 kg
- vr<vs, because some work is done by the rolling ball against the frictional force.
- vr>vs. because the angular velocity acquired makes the rolling ball to travel faster
- vr=vs, because kinetic energy of two balls is same at bottom of planes
- vr<vs, because the rolling ball acquires rotational as well as translational kinetic energy
![](https://df0b18phdhzpx.cloudfront.net/ckeditor_assets/pictures/936341/original_2.png)
- F3 towards left
- 2F3 towards left
- F3 towards right
- Zero
- True
- False
![](https://s3-us-west-2.amazonaws.com/infinitestudent-images/ckeditor_assets/pictures/616086/original_Q01.png)
- The magnitude of the frictional force is F/3.
- The frictional force on the sphere acts forward.
- The acceleration of the centre of mass is 2F/3M.
- The acceleration of the centre of mass is 5F/7M.
Comprehension Type: A uniform thin cylindrical disk of mass M ad radius R is attached to two identical mass less springs of springs constant k which are fixed to the wall as show in the figure. The springs are attached to the axle of the disk symmetrically on either side at a distance d from its center. The axle is mass less and both the springs and the axle are in horizontal plane. The un-stretched length of each springs is L. The disk is initially at its equilibrium position with its center of mass (CM) at a distance L from the wall. The disk rolls without slipping with velocity →(V)0=V0^i The coefficient of friction is μ.
The net external force acting on the disk when its centre of mass is at displacement x with respect to its equilibrium position is
- kx
- 2kx
−2kx3
−4kx3
- 60 J
- 64 J
- 120 J
- 45 J
- Depends on their masses
- Disk
- Sphere
- Both reach at the same time.
![](https://df0b18phdhzpx.cloudfront.net/ckeditor_assets/pictures/1038004/original_3Q.png)
In the arrangement shown in the figure, there is friction between the blocks of masses m and 2m which are in contact. The ground is smooth. The mass of the suspended block is m. The block of mass m which is kept on mass 2m is stationary with respect to a block of mass 2m. The force of friction between m and 2m is (pulleys and string are lig frictionless):
![1137016_e29be7fbb2e5482d9bd9e333639c9948.png](https://search-static.byjusweb.com/question-images/toppr_ext/questions/1137016_e29be7fbb2e5482d9bd9e333639c9948.png)
- mg3
- mg√2
- mg2
- mg4
- Clockwise
- Anticlockwise
![](https://df0b18phdhzpx.cloudfront.net/ckeditor_assets/pictures/1774286/original_img090.jpg)
- 3.8 m
- 1.9 m
- 2 m
- 1.6 m