ICSE Class 6 Physics Important Questions Chapter 7 Simple Machine

Physics ICSE Class 6 Important Questions Chapter 7 Simple Machine

Practice Questions

Question 1.
Give two examples each of : .

1. Simple machines
2. Complex machines
3. Force multiplier
4. Class II lever
5. Class III lever
6. Wheel-and-axle arrangement
7. Speed multiplier

Answer:

1. knife, hammer
2. Sewing machine, car
3. Class II lever (Bottle opener), inclined plane (flyovers)
4. Bottle opener, paper cutter
5. Hockey stick, fishing rod
6. Steering wheel, door knob
7. Class III lever (hockey stick), wheel and axle arrangement (door knob).

Question 2.
Define lever, fulcrum, load, effort, load arm and effort arm.
Answer:

1. A lever is a straight rigid bar that can rotate freely about a point on itself.
2. The fixed point about which the lever can rotate is called the fulcrum (F).
3. The object to be lifted or moved with the help of a lever is called the load (L).
4. The force applied on the lever is called the effort (E).
5. The distance between the load point and the fulcrum is called the load arm.
6. Distance from the effort point to the fulcrum is called the effort arm.

Question 3.
What is mechanical advantage of a lever ?
Answer:
The mechanical advantage of a lever is the ratio between the load lifted by the machine and the effort applied to it, or the ratio between the load arm and the effort arm.Also,
If effort < load, then MA > 1, showing a net mechanical advantage.
If effort > load, then MA < 1. Here there is no mechanical advantage.
If effort = load, then
MA = 1. Here also there is no mechanical advantage.

Question 4.
Name six types of simple machines.
Answer:
Lever, pulley, inclined plane, wheel-and-axle arrangement, screw and wedge.

Question 5.
Fill in the blanks.
(i) Class II and I levers have their effort arm than the load arm, hence their mechanical advantage is always than one and they act as force multipliers.
Answer:
Class II and I levers have their effort arm longer than the load arm, hence their mechanical advantage is always greater than one and they act as force multipliers.

(ii) Class III lever has effort arm ………….. than the load arm, hence their mechanical advantage is always
than one and they act as speed multiplier.
Answer:
Class III lever has effort arm shorter than the load arm, hence their mechanical advantage is always less than one and they act as speed multiplier.

(iii) The amount of push over an inclined plane depends on the ………….. of the load and the ………… of the slope.
Answer:
The amount of push over an inclined plane depends on the weight of the load and the steepness of the slope.

(iv) A single movable pulley has a mechanical advantage of ………….
Answer:
A single movable pulley has a mechanical advantage of two.

(v) In the lever of the first order, ……………. lies between the load and the effort.
Answer:
In the lever of the first order, fulcrum lies between the load and the effort.

(vi) In the lever of the second order, ………….. lies between the effort and the fulcrum.
Answer:
In the lever of the second order, load lies between the effort and the fulcrum.

(vii) In the lever of the third order, …………… lies between the fulcrum and the load.
Answer:
In the lever of the third order, effort lies between the fulcrum and the load.

(viii) A …………. is a cylindrical rod marked with spiral threads.
Answer:
A screw is a cylindrical rod marked with spiral threads.

(ix) A …………. changes the direction of application of the magnitude of force or speed.
Answer:
A pulley changes the direction of application of the force to a convenient direction, without changing the magnitude of force or speed.

ICSE Class 6 Physics Important Questions