a crane hoists a massive object at a constant velocity compared to lifting the same object gradually the work done by the crane is

HESI A2

HESI A2 Physics Practice Test

1. When a crane hoists a massive object at a constant velocity compared to lifting the same object gradually, the work done by the crane is:

A. Less
B. More
C. Identical
D. Dependent on the object's mass

Correct answer: C

Rationale: The work done by the crane is identical in both scenarios. Work is defined as the force applied over a distance. Since the force needed to lift the object is equal to its weight and the displacement is the same, the work done is identical, whether the object is lifted gradually or at a constant velocity. Choice A is incorrect because the work done is the same in both cases. Choice B is incorrect as well since the work done does not increase. Choice D is incorrect as the mass of the object does not affect the work done by the crane in this scenario.

2. What force was applied to the object that was moved if 100 N⋅m of work is done over 20 m?

A. 5 N
B. 80 N
C. 120 N
D. 2,000 N

Correct answer: A

Rationale: Work is calculated using the formula Work = Force x Distance. Given that 100 N⋅m of work is done over 20 m, we can rearrange the formula to solve for Force. Force = Work / Distance. Plugging in the values, we get Force = 100 N⋅m / 20 m = 5 N. Therefore, the force applied to the object that was moved is 5 N. Choice B (80 N) is incorrect because it doesn't match the calculated force of 5 N. Choice C (120 N) is incorrect as it is higher than the calculated force. Choice D (2,000 N) is incorrect as it is significantly higher than the correct force of 5 N.

3. Later he spends $20 on bus tokens. How much is left from his original $100?

A. $49.30
B. $69.30
C. $79.30
D. $89.30

Correct answer: D

Rationale: If he spends $20 on bus tokens from his original $100, then the amount left is $100 - $20 = $80. The remaining 90% of $80 is calculated as $80 + 0.90 * $80 = $80 + $72 = $89.30. Therefore, the correct answer is $89.30. Choices A, B, and C are incorrect as they do not represent the correct calculation of the remaining amount after spending $20.

4. What is 70% of 200?

A. 100
B. 100
C. 200
D. 140

Correct answer: D

Rationale: To find 70% of a number, you multiply the number by 0.70. Therefore, 70% of 200 is calculated as 0.7 × 200 = 140. Choices A, B, and C are incorrect as they do not represent the correct calculation for finding 70% of 200.

5. If 30% of a given number is 18, what is the full number?

A. 60
B. 30
C. 40
D. 45

Correct answer: A

Rationale: If 30% of a number is 18, you can find the full number by dividing 18 by 0.30 (the decimal equivalent of 30%). This calculation results in 60. Therefore, the full number is 60. Choice B (30) is the result if 30% of the number itself was calculated, not the full number. Choices C (40) and D (45) are incorrect and do not align with the given information.