ASVAB Mechanical Comprehension Practice Test 161241 Results

	Your Results	Global Average
Questions	5	5
Correct	0	2.94
Score	0%	59%

Review

Assuming force applied remains constant, which of the following will result in more work being done?

53% Answer Correctly

	increasing the coefficient of friction
	moving the object with more acceleration
	moving the object farther
	moving the object with more speed

Solution

Work is accomplished when force is applied to an object: W = Fd where F is force in newtons (N) and d is distance in meters (m). Thus, the more force that must be applied to move an object, the more work is done and the farther an object is moved by exerting force, the more work is done.

Power is the rate at which:

62% Answer Correctly

	work is done
	friction is overcome
	input force is transferred to output force
	potential energy is converted into kinetic energy

Solution

Power is the rate at which work is done, P = w/t, or work per unit time. The watt (W) is the unit for power and is equal to 1 joule (or newton-meter) per second. Horsepower (hp) is another familiar unit of power used primarily for rating internal combustion engines. 1 hp equals 746 watts.

3 How much work can a 6 hp engine do in 10 seconds?

52% Answer Correctly

	0 ft⋅lb
	33000 ft⋅lb
	12 ft⋅lb
	3 ft⋅lb

Solution

Horsepower (hp) is a common measure of power output for complex machines. By definition, a 1 hp machine does 550 ft⋅lb of work in 1 second: 1 hp = 550 ft⋅lb/s. Substituting the variables for this problem gives us:
\( W = 6 hp \times 550 \frac{ft⋅lb}{s} \times 10s = 33000 ft⋅lb \)

The force exerted on an object due to gravity is called:

70% Answer Correctly

	mass
	density
	potential energy
	weight

Solution

Mass is an intrinsic property of matter and does not vary. Weight is the force exerted on the mass of an object due to gravity and a specific case of Newton's Second Law of Motion. Replace force with weight and acceleration with acceleration due to gravity on Earth (g) and the result is the formula for weight: W = mg or, substituting for g, weight equals mass multiplied by 9.8 m/s².

Which of these will have the most impact on the kinetic energy of an object?

54% Answer Correctly

	its weight
	its mass
	its speed
	its direction

Solution

Kinetic energy is the energy of movement and is a function of the mass of an object and its speed: \(KE = {1 \over 2}mv^2\) where m is mass in kilograms, v is speed in meters per second, and KE is in joules. The most impactful quantity to kinetic energy is velocity as an increase in mass increases KE linearly while an increase in speed increases KE exponentially.