# Homework for XI/group A/SHIKSHA/Saturday/29-09-2018

Q1.  A force of 200 N is applied to a block of mass 20 kg on an inclined plane at 53 º with the horizontal .

(i)  What will be the acceleration of the block in downward direction ?

(II) How much force is required to move it in up along the plane ?

(iii) How much force is required to keep the body at rest on the inclined plane ?

Q2.  Write down some of the advantages and disadvantages of friction

Q3. 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, ahorizontal force of 60 N is required to keep the block moving  with constant speed. Find the coefficient of static  and kinetic friction .

Q4. A body of 5 kg weight kept on a rough inclined plane of angle 30º starts  sliding with a constant velocity. Then find the coefficient of friction . (assume  g = 10 m/s²)

Q5. Define the following terms

Sliding friction , limiting friction , angle of friction , coefficient of kinetic friction , angle of repose .