{"id":25779,"date":"2021-06-24T11:23:03","date_gmt":"2021-06-24T05:53:03","guid":{"rendered":"https:\/\/ncertsolutions.guru\/?p=25779"},"modified":"2021-06-24T11:23:03","modified_gmt":"2021-06-24T05:53:03","slug":"ncert-solutions-for-class-8-science-chapter-12","status":"publish","type":"post","link":"https:\/\/ncertsolutions.guru\/ncert-solutions-for-class-8-science-chapter-12\/","title":{"rendered":"NCERT Solutions for Class 8 Science Chapter 12 Friction"},"content":{"rendered":"

These NCERT Solutions for Class 8 Science<\/a> Chapter 12 Friction Questions and Answers are prepared by our highly skilled subject experts to help students while preparing for their exams.<\/p>\n

Friction NCERT Solutions for Class 8 Science Chapter 12<\/h2>\n

Class 8 Science Chapter 12 Friction Textbook Exercise Questions and Answers<\/h3>\n

Page-155<\/span><\/p>\n

Question 1.
\nFill in the blanks:
\na. Friction opposes the ……………. between the surfaces in contact with each other.
\nb. Friction depends on the ……………. of surfaces.
\nc. Friction produces …………….
\nd. Sprinkling of powder on the carrom board ……………. friction.
\ne. Sliding friction is ……………. than the static friction.
\nAnswer:
\na. motion,
\nb. nature,
\nc. heat,
\nd. reduces,
\ne. less<\/p>\n

Question 2.
\nFour children were asked to arrange forces due to rolling, static and sliding frictions in a \u2018decreasing order\u2019.
\nTheir arrangements are given below. Choose the correct arrangement.
\na. rolling, static, sliding
\nb. rolling, sliding, static
\nc. static, sliding, rolling
\nd. sliding, static, rolling
\nAnswer:
\nc. static, sliding, rolling<\/p>\n

Question 3.
\nAlida runs her toy car on dry marble floor, wet marble floor, newspaper and towel spread on the floor. The force of friction acting on the car on different surfaces in \u2018increasing order\u2019 will be:
\na. wet marble floor, dry marble floor, newspaper and towel.
\nb. newspaper, towel, dry marble floor, wet marble floor.
\nc. towel, newspaper, dry marble floor, wet marble floor.
\nd. wet marble floor, dry marble floor, tow el, newspaper
\nAnswer:
\na. wet marble floor, dry marble floor, newspaper and towel.<\/p>\n

Question 4.
\nSuppose your writing desk is tilted a little. A book kept on it starts sliding down. Show the direction of frictional force acting on it.
\nAnswer:
\nWhen book slides down the desk, a frictional force acts between the book and the surface of the desk. The direction of the frictional force on the book is opposite to the direction of its motion and acts in an upward direction. It is shown in the diagram below:
\n\"NCERT<\/p>\n

Question 5.
\nYou spill a bucket of soapy water on a marble floor accidently. Would it make it easier or more difficult for you to walk on the floor? Why?
\nAnswer:
\nWe are able to walk because of the friction present between our feet and the ground. In order to walk, we push the ground in the backward direction with our feet. The force of friction pushes it in the forward direction and allows us to walk. The force of friction between the ground and feet decreases when there is soapy water spilled on the floor. It acts as a lubricant. Hence, it becomes difficult to walk on the soapy floor.<\/p>\n

\"NCERT<\/p>\n

Question 6.
\nExplain why sportsmen use shoes with spikes.
\nAnswer:
\nShoes with spikes offer more friction because of more irregularities in the surface. This gives better grip to sportsmen while running.<\/p>\n

Question 7.
\nIqbal has to push a lighter box and Seema has to push a similar heavier box on the same floor. Who will have to apply a larger force and why?
\nAnswer:
\nForce of friction arises because of interlocking of irregularities on the two surfaces in contact. When a heavy object is placed on the floor, the interlocking of irregularities on the surfaces of box and floor becomes strong. This is because the two surfaces in contact are pressed harder. Hence, more force is required to overcome the interlocking. Thus, to push the heavier box, Seema has to apply a greater force than Iqbal.<\/p>\n

Question 8.
\nExplain why the sliding friction is less than the static friction.
\nAnswer:
\nWhen something is static, a greater force is required to break the interlocking between two surfaces. When something is in motion, the surfaces do not get enough time to interlock properly and a smaller force is required to keep the object in motion. Hence, sliding friction is less than static friction.<\/p>\n

Question 9.
\nGive examples to show that friction is both a friend and a foe.
\nAnswer:
\nFollowing two examples show that friction is both a friend and a foe:
\nFriction as a friend:<\/p>\n