Energy and simple machines Quiz - ICSE Class 7 Science

Free practice quiz: Energy and simple machines (ICSE Class 7 Science). 48 multiple-choice questions with answers and explanations. Play online, no sign-up needed.

Sample questions

1. A lever is a rigid bar that pivots around a fixed point called a fulcrum. Which class of lever has the fulcrum between the effort and the load?

   1. Class 1 lever
   2. Class 2 lever
   3. Class 3 lever
   4. All levers
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   Answer: A. Class 1 lever

   In a Class 1 lever, the fulcrum is positioned between the effort (input force) and the load (output force). Examples include a seesaw or a crowbar.

2. What is the main advantage of using a Class 2 lever over a Class 1 lever in certain situations?

   1. It requires less effort to move the load.
   2. The effort is applied closer to the fulcrum.
   3. It can be used to change the direction of force more effectively.
   4. It always provides a greater mechanical advantage.
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   Answer: A. It requires less effort to move the load.

   In a Class 2 lever, the load is between the fulcrum and the effort. This arrangement typically results in a mechanical advantage greater than 1, meaning the effort force required is less than the load force. Examples include a wheelbarrow or nutcrackers.

3. A compound machine is made up of:

   1. Only one simple machine
   2. Two or more simple machines
   3. Only levers
   4. Only pulleys
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   Answer: B. Two or more simple machines

   A compound machine is a machine made up of two or more simple machines working together. For example, a bicycle uses wheels and axles, levers (pedals and handlebars), and screws (bolts).

4. A system of gears is often used to:

   1. Increase or decrease speed
   2. Increase or decrease torque
   3. Change the direction of rotation
   4. All of the above
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   Answer: D. All of the above

   By changing the number of teeth on meshing gears, their relative sizes, and their arrangement, a gear system can effectively modify rotational speed, torque (rotational force), and direction of rotation to suit different applications.

5. A winding staircase is an example of:

   1. A lever
   2. A pulley system
   3. An inclined plane
   4. A wheel and axle
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   Answer: C. An inclined plane

   A staircase is essentially a series of inclined planes. By walking up a staircase, you are moving upwards over a longer distance with less effort than if you were to climb straight up a vertical wall.

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