1.
How many classes of levers are there?
Correct Answer
C. Three
Explanation
There are three classes of levers. This classification is based on the relative positions of the fulcrum, effort, and load in a lever system. In a class 1 lever, the fulcrum is located between the effort and load. In a class 2 lever, the load is located between the fulcrum and effort. In a class 3 lever, the effort is located between the fulcrum and load. Each class of lever has different mechanical advantages and applications.
2.
A baseball bat is an example of this class of lever:
Correct Answer
C. Third-class
Explanation
A baseball bat is an example of a third-class lever because the effort (force applied by the batter) is located between the fulcrum (the batter's hands) and the load (the ball). In a third-class lever, the force arm (distance between the fulcrum and the effort) is shorter than the load arm (distance between the fulcrum and the load), which means that the effort has to be greater than the load to achieve the desired result.
3.
The formula for the mechanical advantage of an inclined plane is:
Correct Answer
B. Distance divided by height
Explanation
The correct answer is "distance divided by height". This formula represents the mechanical advantage of an inclined plane, where the input arm is the distance and the output arm is the height. Dividing the distance by the height gives us the ratio of how much the load is reduced or how much easier it is to move the load up the inclined plane.
4.
All of these are examples of inclined planes except:
Correct Answer
E. Wheel
Explanation
The wheel is not an example of an inclined plane because it is a circular object that rotates around an axle, rather than being a flat surface inclined at an angle. Inclined planes are typically flat surfaces that are sloped, such as a ramp, staircase, or slide, which allow objects to be moved up or down with less force. A hatchet is not an inclined plane either, as it is a tool used for cutting or chopping.
5.
All of these are types of gears except:
Correct Answer
A. Snake
6.
These two simple machines make a screw:
Correct Answer
B. Inclined plane and wedge
Explanation
An inclined plane and a wedge are two simple machines that can be used to make a screw. An inclined plane is a flat surface that is sloped, which allows for the gradual increase in height or distance covered. A wedge is a triangular-shaped object that is used to separate or lift objects apart. In the case of making a screw, the inclined plane can be used to create the spiral shape of the screw, while the wedge can be used to cut or carve the threads into the screw. Together, these two simple machines can be used to create a screw.
7.
What simple machine combines with itself to make a wedge?
Correct Answer
B. Inclined plane
Explanation
A wedge is a simple machine that is formed by two inclined planes joined together. When the inclined planes are pushed together, they create a sharp edge, which allows the wedge to be used for splitting or cutting objects. Therefore, the correct answer is inclined plane, as it combines with itself to form a wedge.
8.
All of these are examples of a wheel and axle except:
Correct Answer
A. Nail
Explanation
A wheel and axle is a simple machine that consists of a wheel attached to a smaller axle. The wheel and axle work together to allow for the movement and transfer of force. In this case, all the options listed (rolling pin, roller skates, door knob, and windmill) have a wheel and axle mechanism. However, a nail does not have a wheel and axle mechanism, as it is a pointed metal object used for fastening objects together.
9.
The handles of a pair of scissors are an example of this type of simple machine.
Correct Answer
E. Lever
Explanation
The handles of a pair of scissors act as a lever. A lever is a simple machine that consists of a rigid bar that pivots on a fixed point called a fulcrum. In the case of scissors, the fulcrum is the screw that holds the two blades together. When pressure is applied to the handles, it causes the blades to pivot around the fulcrum, allowing them to cut through materials. Therefore, the handles of a pair of scissors demonstrate the principle of a lever.
10.
What is a simple machine that uses grooved wheels and a rope to raise, lower, or moves a load?
Correct Answer
D. Pulley
Explanation
A pulley is a simple machine that uses grooved wheels and a rope to raise, lower, or move a load. The grooved wheels, called sheaves, are connected by a rope or cable, and when force is applied to one end of the rope, the load on the other end is lifted or moved. Pulleys are commonly used in systems such as elevators, cranes, and flagpoles to make it easier to lift heavy objects.