Friction (Assignment)
![CBSE Class 8 - Science - Friction (Assignment) (#cbseNotes) CBSE Class 8 - Science - Friction (Assignment) (#cbseNotes)](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhT-_Ym8LWDL2NWKKCDPB8cVrLX2m9Io-Mbde0Up-HW6zYkdb_boo24vVHOPrSv_9Jh9feCsk4NzGl81LAqrT48w6xVXEsqSnV1wOjxE3QTuy4JZK3LOb3zlr0bgArwep7BpJ3qLFJUyFao/s400/cl8SciCh12Fig2.jpg)
Q1: Name the following:
⒜ Type of surfaces that produces minimum friction _____________
⒝ Type of surfaces that produce maximum friction _____________
⒞ A shape that reduces drag _____________
⒟ Friction with minimum magnetic magnitude _____________
⒠ Friction with maximum magnitude _____________
⒡ Two types of fluids _____________
⒢ Frictional force exerted by fluids _____________
⒣ A device that converts sliding friction
into rolling friction _____________
⒤ A self-adjusting force which opposes the
relative motion of two surfaces _____________
⒥ Graphite powder, grease, oils are examples of _____________
Q2: Fill in the blanks
⒜ Force always opposes the motion ________________.
⒝ Is a device used to measure force acting on an object _______________.
⒞ Ball bearing is commonly used in bicycle wheels to _________ friction.
⒟ Gymnasts apply of course substance on their hands to ________ friction.
⒠ Frictional force is an example of ____________ force.
⒡ Limiting friction is ___________ of the area of contact.
⒢ Force of static friction is ___________ ___________.
Q3: Complete the table given below
Advantages of friction | Disadvantages of friction | |
---|---|---|
1. | Help us write | Leads to wastage of energy |
2. | ||
3. | ||
4. | ||
5. | ||
6. |
Answers:
Q1:
⒜ smooth/polished surface
⒝ rough surface
⒞ streamlined shape
⒟ rolling friction
⒠ static friction
⒡ liquids and gases
⒢ fluid friction or drag
⒣ ball bearing/ wheel
⒤ friction
⒥ lubricants
Q2:
⒜ friction
⒝ spring balance
⒞ reduce/decrease
⒟ increase
⒠ contact
⒡ independent
⒢ self adjusting
Q3:
Advantages of friction | Disadvantages of friction | |
---|---|---|
1. | Help us write | Leads to wastage of energy |
2. | Help us wal | Friction produces heat which reduces the efficiency of machines. |
3. | Allows vehicles to move on the road. | leads to wear and tear of machine parts |
4. | Enables us light a matchstick | Drag slows down the speed of the object. |
5. | Can write on blackboard with a checque. | Soles of shoes wear down due to friction. |
6. | Enables us write down on a page using pen or pencil. | Due to friction, engines of automobiles consume more fuel, hence increases costs. |
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