Textbook Question
Zach, whose mass is 80 kg, is in an elevator descending at 10 m/s. The elevator takes 3.0 s to brake to a stop at the first floor. (a) What is Zach's weight before the elevator starts braking?
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Ch 06: Dynamics I: Motion Along a Line
Chapter 6, Problem 6
A woman has a mass of 55 kg. (a) What is her weight while standing on earth?
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Weight
Weight is the force exerted on an object due to gravity. It is calculated using the formula W = mg, where W is weight, m is mass, and g is the acceleration due to gravity. On Earth, g is approximately 9.81 m/s², which means that an object's weight varies depending on its mass and the gravitational field strength.
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10:19
Torque Due to Weight
Mass
Mass is a measure of the amount of matter in an object, typically measured in kilograms (kg). Unlike weight, mass does not change regardless of the object's location in the universe. It is a scalar quantity and is fundamental in determining how much gravitational force an object will experience.
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Gravitational Acceleration
Gravitational acceleration is the acceleration experienced by an object due to the force of gravity. On the surface of the Earth, this value is approximately 9.81 m/s². This constant is crucial for calculating weight, as it represents the rate at which an object accelerates towards the Earth when falling freely.
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Related Practice
Textbook Question
It takes the elevator in a skyscraper 4.0 s to reach its cruising speed of 10 m/s. A 60 kg passenger gets aboard on the ground floor. What is the passenger's weight (a) Before the elevator starts moving?
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Textbook Question
It takes the elevator in a skyscraper 4.0 s to reach its cruising speed of 10 m/s. A 60 kg passenger gets aboard on the ground floor. What is the passenger's weight (c) After the elevator reaches its cruising speed?
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Textbook Question
The mass of the sun is 2.0 x 10^30 kg. A 5.0 x 10^14 kg comet is 75 million kilometers from the sun. What is the magnitude of the comet's acceleration toward the sun?
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Textbook Question
Astronauts in space 'weigh' themselves by oscillating on a spring. Suppose the position of an oscillating 75 kg astronaut is given by x = (0.30 m) sin ((𝝅 rad/s) X t), where t is in s. What force does the spring exert on the astronaut at (a) t = 1.0 s and (b) 1.5 s? Note that the angle of the sine function is in radians.
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Textbook Question
A ball is shot from a compressed-air gun at twice its terminal speed.
a. What is the ball's initial acceleration, as a multiple of g, if it is shot straight up?
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