What would be Kelly's weight in newtons if her mass is 70 kilograms?
A. [tex]$70 \times g$[/tex]
B. 70
g
C. 70
[tex]$g^2$[/tex]
D. [tex]$70 \times g^2$[/tex]
E. 70
Answer (1)
Weight is calculated by multiplying mass by the acceleration due to gravity.
Kelly's mass is 70 kg.
Weight = mass × g = 70 × g .
Therefore, Kelly's weight is 70 × g .
Explanation
Understanding the Problem We are given Kelly's mass, which is 70 kilograms, and we need to find her weight in newtons. Weight is the force exerted on an object due to gravity. The formula to calculate weight is: Weight = mass × acceleration due to gravity.
Identifying Given Values The mass (m) is given as 70 kg. The acceleration due to gravity (g) is approximately 9.8 m / s 2 .
Calculating Weight To find Kelly's weight (W) in newtons, we use the formula: W = m × g . Substituting the given values, we get: W = 70 × g . Therefore, Kelly's weight is 70 × g newtons.
Final Answer The correct answer is A. 70 × g
Examples
Understanding weight is crucial in many real-world scenarios. For example, when designing bridges, engineers need to calculate the weight of the materials and the vehicles that will cross the bridge to ensure it can support the load. Similarly, in aerospace engineering, calculating the weight of a satellite is essential for determining the amount of fuel needed to launch it into orbit. In everyday life, knowing the weight of objects helps us estimate the force needed to lift or move them, preventing injuries and making tasks more efficient.
