FREE SIFT Mechanical Comprehension Questions and Answers

Question 1

Christian takes thirty steps forward, followed by thirty steps backward. In terms of his total distance, how many steps has Christian taken?

Accepted Answer

60

Answer

The question asks for Christian's total distance, which refers to the entire length of the path he traveled, regardless of direction. Christian took thirty steps forward and then thirty steps backward. Therefore, his total distance covered is the sum of these two movements: 30 steps + 30 steps = 60 steps. This is distinct from displacement, which would be zero since he returned to his starting point.

Question 2

Danny, a young man from the Northern Hemisphere, is positioned on a scale. Danny is 20 kg heavy. In Newtons, the scale readout is shown. What is Danny's readout?

Accepted Answer

196

Answer

Weight is a force, measured in Newtons, and is calculated by multiplying an object's mass by the acceleration due to gravity (g). The acceleration due to gravity on Earth is approximately 9.8 meters per second squared (m/s²). Therefore, Danny's weight is 20 kg * 9.8 m/s² = 196 Newtons. The scale readout would display this force.

Question 3

An inclined plane's strength increases as its

Accepted Answer

Mechanical Advantage

Answer

An inclined plane's 'strength' in terms of making work easier is its ability to reduce the effort force required to move an object. This is quantified by its mechanical advantage. A higher mechanical advantage means that a smaller input force is needed to overcome a larger resistance force, effectively increasing the ease or 'strength' of the simple machine.

Question 4

The mechanical advantage of a lever with 250 N of resistance and 50 N of effort is

Accepted Answer

5

Answer

Mechanical advantage (MA) is calculated as the ratio of the resistance force (output force) to the effort force (input force). In this case, the resistance force is 250 N and the effort force is 50 N. Therefore, the mechanical advantage is 250 N / 50 N = 5. This means the lever multiplies the applied effort by a factor of 5.

Question 5

2 m are raised by a 50 N vase. What work is completed?

Accepted Answer

100J

Answer

Work is defined as the product of the force applied to an object and the distance over which that force is applied in the direction of motion. In this scenario, the force required to raise the vase is its weight, 50 N, and the distance it is raised is 2 m. Therefore, the work completed is 50 N * 2 m = 100 Joules.

SIFT Exam Practice Test

SIFT Exam Practice Test

FREE SIFT Mechanical Comprehension Questions and Answers