Free WTMA Mechanical Comprehension Questions and Answers

Question 1

What is the ratio of the pulling force F to the load L if the weight of each pulley is equal to the load? (F / L =?)

Accepted Answer

1

Answer

In an ideal pulley system, the ratio of the pulling force (F) to the load (L) is equal to 1 divided by the mechanical advantage (MA). If the ratio F/L is 1, it implies that the pulling force is equal to the load. This scenario typically occurs with a single fixed pulley, which only changes the direction of the force but does not provide any mechanical advantage in terms of reducing the force required to lift the load. The information about the weight of each pulley is a distractor for this ideal scenario.

Question 2

A force of 1200 N is used to hold a 300 N load. What is the lever's length in meters if the force is acting at a location 25 cm from the fulcrum?

Accepted Answer

1

Answer

The principle of moments states that for a lever to be in equilibrium, the clockwise moment must equal the counter-clockwise moment. This means Force1 × Distance1 = Force2 × Distance2. Given an effort force of 1200 N acting at 0.25 m (25 cm) from the fulcrum, and a load of 300 N, we can calculate the distance of the load from the fulcrum: 1200 N × 0.25 m = 300 N × d_load. Solving for d_load gives 300 Nm = 300 N × d_load, so d_load = 1 meter. This represents the length of the load arm of the lever.

Question 3

Which type of lever is used by the hydraulic crane in the illustration?

Accepted Answer

Third class lever

Answer

A third-class lever has the effort applied between the fulcrum and the load. In a typical hydraulic crane boom, the pivot point where the boom attaches to the crane body acts as the fulcrum. The hydraulic cylinder applies the effort force somewhere along the boom, between the fulcrum and the load, which is lifted at the end of the boom. This configuration prioritizes range of motion and speed over force advantage.

Question 4

If one wants to raise the load in the figure by 28 inches, how many inches does one need to draw the rope down?

Accepted Answer

56 in

Answer

In a pulley system, the distance the effort rope must be pulled is directly related to the mechanical advantage (MA) of the system. If the load is lifted by a certain distance, the rope must be pulled by that distance multiplied by the mechanical advantage. For a system where the rope needs to be drawn down twice the distance the load is raised (56 inches for a 28-inch lift), the mechanical advantage is 2. This means the system uses a movable pulley or a block and tackle with two supporting rope segments.

Question 5

Which process DOES NOT involve using a magnet?

Accepted Answer

Painting method

Answer

The stroking method and electrical method are both established ways to magnetize materials, directly involving the use of existing magnets or creating magnetic fields. The painting method, however, refers to applying paint to a surface and has no direct connection to magnetism or the process of magnetizing an object. It is a distractor among methods related to magnetism.

WTMA - Wiesen Test of Mechanical Aptitude Practice Test

WTMA - Wiesen Test of Mechanical Aptitude Practice Test

Free WTMA Mechanical Comprehension Questions and Answers