Objective questions of of chapter -4 (based on simple machine) of class 6.

 A. Objective questions

1. State whether the following statements are true or false:

a) A boy does work while pushing a wall.

Ans. False.

A boy does not do  any work while pushing a wall.

b) A machine performs work by itself.

Ans. False.

A machine does not work by itself.

c) in an ideal machine, work done on load is equal to the work done by effort.

Ans. True.

d) all levers are force multipliers.

Ans. False.

All levers are not force multipliers. Class 3 lever is is a speed multiplier. Class 2 lever is a force multiplier. Class 1 lever may acts as a force multiplier or speed multiplier  or direction changer.

e) A pulley changes the direction of force.

Ans. True.

f) an inclined plane always has the mechanical advantage more than 1.

Ans. True

2. Fill in the blanks:

a) the useful work done by an actual machine is always..less... then the work done on the machine.

b) in class two levers, the.. load... is in in between fulcrum and ... Effort...

c) the mechanical advantage of class..3.... Lever is always less than 1.

d) a pulley is used to change... The direction of effort....

e) mechanical advantage of an inclined plane is always.. greater than one....

3)match the following columns:

a) needle - wedge

b) door knob- wheel and axle

c) ramp- inclined plane

d) lemon crusher- class 2 lever

e) see-saw- class 1 lever.

4. Select the correct alternatives:

1. For an ideal machine, the efficiency is

a) greater than unity.

b) less than unity.

c) equal to unity.

d) depends on the value of load.

2. Mechanical advantage of a machine is defined as:

a) load×effort

b) load/effort

c) load+effort

d) effort/load

3. The mechanical advantage of a lever is equal to:

a) load arm/effort arm.

b) effort arm/load arm

c) load arm+effort arm

d) load arm-effort arm

4. A pulley is used because it

a) has the mechanical advantage greater than 1.

b has 100% efficiency.

c) helps to apply the force in a convenient direction.

d) requires more effort to raise a less load.

5. Wheel is used with axle because

a) sliding friction is less than the rolling friction.

b) rolling friction a less than the sliding friction.

c) they work as the inclined plane.

d) they help us to change the direction of force.