Choose the correct answer :

1. Efficiency of a machine is −
   1. output × input
   2. output/input
   3. input/output
   4. output + input
2. Levers are of −
   1. one type
   2. two types
   3. three types
   4. four types 
3. For levers of first order −
   1. MA = 1
   2. MA > 1
   3. MA < 1
   4. all of these
4. For levers of third order −
   1. MA = 1
   2. MA < 1
   3. MA > 1
   4. MA = 0
5. Doorknob is an example of a/an −
   1. inclined plane
   2. wheel and axle
   3. wedge
   4. screw
6. A wirecutter is an example of a −
   1. level of first order
   2. level of second order
   3. level of third order
   4. None of these
7. In case of a movable pulley −
   1. MA = 1
   2. MA > 2
   3. MA < 1
   4. MA = 2
8. Mechanical advantage of a machine is −
   1. Load × Effort
   2. Load / Effort
   3. Load + Effort
   4. Effort / Load

Fill in the blanks :

1. A jack is used to ________________________ force.
2. A nutcracker is a lever of ____________________________ order.
3. In levers of first order ___________________ is in between load and effort.
4. Levers of second order act as _________________ multiplier.
5. A single fixed pulley is used to ______________________ the direction of applied force.
6. Mechanical advantage of a machine is _____________________ than 100 per cent.
7. Chisel is an example of ________________.
8. Steering wheel is an example of __________________ .
9. A crowbar is a lever of ____________________ order.
10. Moving parts of a machine are lubricated to ______________________ friction.

Write True (T) or False (F) against the following statements :

1. A bicycle is an example of a simple machine.
2. A staircase is an example of a screw.
3. Levers of third order help us to multiply force.
4. A nail is an example of a lever.
5. The ratio of load to the effort is called velocity ratio of a machine.
6. Friction reduces efficiency of a machine.
7. A doorknob is an example of a screw.
8. A screw driver is an example of a wheel and axle.
9. The efficiency of a machine is always greater than 100 per cent.
10. Single fixed pulley is an example of a lever of second order.

Match the following :

With proper reasoning, choose the odd one out :

1. fire tong, bottle opener, see-saw, bolt
2. inclined plane, screw, wedge, watch
3. bottle opener, wheelbarrow, nutcracker, human forearm
4. ramp, staircase, wheel, wooden plank
5. crowbar, a pair of scissors, lemon squeezer, beam balance