Question

To understand the distinction between mass and weight and to be able to calculate the weight of an object from its mass and Newton's law of gravitation. The concepts of mass and weight are often confused. In fact, in everyday conversations, the word "weight" often replaces "mass," as in "My weight is seventy-five kilograms" or "I need to lose some weight." Of course, mass and weight are related; however, they are also very different. Mass, as you recall, is a measure of an object's inertia (ability to resist acceleration). Newton's 2nd law demonstrates the relationship among an object's mass, its acceleration, and the net force acting on it: F net=ma . Mass is an intrinsic property of an object and is independent of the object's location. Weight, in contrast, is defined as the force due to gravity acting on the object. That force depends on the strength of the gravitational field of the planet: W =mg , where W is the weight of an object, m is the mass of that object, and g⃗is the local acceleration due to gravity (in other words, the strength of the gravitational field at the location of the object). Weight, unlike mass, is not an intrinsic property of the object; it is determined by both the object and its location. Which of the following quantities would be acceptable representations of weight? Check all that apply.

A.) 12.0 lb
B.) 0.34 g
C.) 120 kg
D.) 1600 kN
E.) 0.34 m
F.) 411 cm

Answer 1

Answer: A.E.

Explanation: To understand the distinction between mass and weight and to be able to calculate the weight of an object from its mass and Newton's law of gravitation. The concepts of mass and weight are often confused. In fact, in everyday conversations, the word "weight" often replaces "mass," as in "My weight is seventy-five kilograms"

Answer 2

Answer: Option D: 1600 kN

Explanation: The concepts of mass and weight are different, the mass is calculated in grams, and the weight is calculated, like a force, in newtons (or other units of force).

So if we are looking for representations of weight, we are looking for representations of force.

Options A, B and C are written in units of mass (lb, g, kg)

Option D, 1600kN is written in newtons, si it has units of force, this is an acceptable representation of weight.

Options E and F are in units of distance (m, cm)