A body needs a force F₁ just to start motion on a surface, a force F₂ to continue its motion and a force F₃ to roll on the surface. What is

1. the static friction
2. sliding friction and
3. rolling friction ? State whether F₂ is equal, less than or greater than (1) F₁ and (2) F₃.

Q. A body needs a force $F_1$ just to start motion on a surface, a force $F_2$ to continue its motion and a force $F_3$ to roll on the surface. What isState whether $F_2$ is equal, less than or greater than $\left(i\right)F_{1}and\left(ii\right)F_3$.

Q. Four blocks of the same material, $m_1,m_2,m_3$ and $m_4$ have masses $2kg,4kg,2.5kg$ and $2kg$ respectively. All of them have equal surface area in contact with the concrete surface over which they are kept. Let the frictional force acting on them be $F_1,F_2,F_3$ and $F_4$ respectively.
The correct order of friction force acting on them when they slide is:

Q. Which of the following statements is incorrect?
(a) static friction is greater than rolling friction
(b) sliding friction is less than rolling friction
(c) rolling friction is less than static friction
(d) static friction is greater than sliding friction

Q. A force $F_1$ accelerates a particle from rest to a velocity $v$. Another force $F_2$ decelerates the same particle from $v$ to rest, then

Q.

The forces F₁, F_2, and F₃ are acting on a particle of mass m, such that F₂ and F₃ are mutually perpendicular and under the effect of F₁, F_2, and F₃ , the particle remains stationary. What will be the acceleration of the particle, if the force F₁ is removed?