[كينزى114]

السلام عليكم و رحمة الله و بركاته
دى اسئلة و اجوبة الوحدة الاولى( الاحتكاك)
و للامانة منقول
و اتمنى ان تستفيدوا منها و لا تنسونا با الدعاء
و انشاء الله باقى الوحدات قريبا انشاء الله



Question one:

Complete the following:
1- The friction force can be observed between ……… and ……… .
bicycle tyre – ground


2- The friction force affects in ……… direction of ……… .
opposite – movement


3- The ……… force exists between two forces.
friction


4- When the cube slides down on the wooden board, the friction force is ……… .
small


5- The friction force between two surfaces made of glass is ……… than friction between glass and metal.
smaller


6- The friction causes ……… for parts of machines.
damage


7- The temperature rises inside machines is due to ……… .
friction


8- Friction forces can be decreased by using ……… and ……… .
lubricants – oil


9- Technicians use ……… to decrease friction in wheels.
ball bearing


10- The smooth surface of balls in ball bearing makes the friction force ……… .
almost non-exits




Question one:
Complete the following:
1- The friction force can be observed between ……… and ……… .
bicycle tyre – ground


2- The friction force affects in ……… direction of ……… .
opposite – movement


3- The ……… force exists between two forces.
friction


4- When the cube slides down on the wooden board, the friction force is ……… .
small


5- The friction force between two surfaces made of glass is ……… than friction between glass and metal.
smaller


6- The friction causes ……… for parts of machines.
damage


7- The temperature rises inside machines is due to ……… .
friction


8- Friction forces can be decreased by using ……… and ……… .
lubricants – oil


9- Technicians use ……… to decrease friction in wheels.
ball bearing


10- The smooth surface of balls in ball bearing makes the friction force ……… .
almost non-exits

Question five:
Write two methods to decrease friction force.
1- Using lubricants and oil.
2- Using ball bearing.


Question six:
Explain why we need to push bicycle tyres to move.
Because there is a friction force between tyres and the ground.