Free IST Mechanical Aptitude Questions and Answers

Question 1

Which type of simple machine is a seesaw?

Accepted Answer

Lever

Answer

A seesaw is a classic example of a lever, specifically a Class 1 lever. It consists of a rigid bar (the board) that pivots around a fixed point called a fulcrum (the central support). The effort force is applied on one side, and the load (the person) is on the other, demonstrating how levers can multiply force or change the direction of motion.

Question 2

If Gear A has 20 teeth and Gear B has 40 teeth, how many rotations will Gear A make when Gear B makes one rotation?

Accepted Answer

2 rotations

Answer

The relationship between the rotations of two meshed gears is inversely proportional to their number of teeth. Since Gear B has twice as many teeth as Gear A (40 teeth vs. 20 teeth), Gear A must rotate twice for every single rotation of Gear B to maintain the same linear speed at the point of contact. Therefore, Gear A will make 2 rotations.

Question 3

Which of the following describes the mechanical advantage of an inclined plane?

Accepted Answer

The length of the plane divided by the height of the plane

Answer

The mechanical advantage (MA) of an inclined plane is calculated by dividing the length of the inclined surface by its vertical height. This ratio indicates how much the input force is multiplied, making it easier to move an object vertically by pushing it along a longer, gentler slope. A higher MA means less effort is required.

Question 4

Which principle explains why a hydraulic press can lift a heavy object with a small force?

Accepted Answer

Pascal's Principle

Answer

Pascal's Principle states that a pressure change at any point in a confined incompressible fluid is transmitted throughout the fluid such that the same change occurs everywhere. In a hydraulic press, a small force applied to a small piston creates pressure that is transmitted to a larger piston, resulting in a much larger force capable of lifting heavy objects.

Question 5

What happens to the effort force required to lift a load if the length of the lever arm is increased?

Accepted Answer

It decreases

Answer

For a lever, the principle of moments (or torque) states that the effort force multiplied by the length of the effort arm equals the load force multiplied by the length of the load arm. If the length of the effort arm is increased while the load and load arm remain constant, the effort force required to balance or lift the load must decrease. This is why longer wrenches make it easier to turn bolts.

IST - Industrial Skills Test Practice Test

IST - Industrial Skills Test Practice Test

Free IST Mechanical Aptitude Questions and Answers