The table shows the masses of four objects.
Object Mass (kg)
Book 1.1
Rock 2.3
Box 4.5
Fish 5.8
Which object has a weight of about 22.5 N?
Answer (1)
Calculate the weight of each object using W e i g h t = M a ss × 9.8 s 2 m .
W e i g h t b oo k = 1.1 k g × 9.8 s 2 m = 10.78 N
W e i g h t roc k = 2.3 k g × 9.8 s 2 m = 22.54 N
The rock has a weight closest to 22.5 N, so the answer is the rock: t h eroc k .
Explanation
Problem Analysis We are given the masses of four objects and asked to find which object has a weight of approximately 22.5 N. We know that weight is calculated by multiplying mass by the acceleration due to gravity, which we will approximate as 9.8 m/s^2.
Calculating Weights We will calculate the weight of each object using the formula: W e i g h t = M a ss × 9.8 s 2 m .
Calculating Each Object's Weight
Book: W e i g h t b oo k = 1.1 k g × 9.8 s 2 m = 10.78 N
Rock: W e i g h t roc k = 2.3 k g × 9.8 s 2 m = 22.54 N
Box: W e i g h t b o x = 4.5 k g × 9.8 s 2 m = 44.1 N
Fish: W e i g h t f i s h = 5.8 k g × 9.8 s 2 m = 56.84 N
Identifying the Closest Weight Comparing the calculated weights to 22.5 N, we see that the weight of the rock (22.54 N) is the closest to 22.5 N.
Final Answer Therefore, the object with a weight of about 22.5 N is the rock.
Examples
Understanding weight and mass is crucial in many real-world scenarios. For instance, when designing bridges, engineers need to calculate the weight of materials to ensure structural integrity. Similarly, in sports, knowing the weight of equipment like a baseball bat or a weightlifting bar is essential for performance and safety. This concept also applies to everyday activities such as packing a suitcase, where understanding the weight of items helps avoid exceeding airline weight limits.
