An object is in motion if its distance relative to another object is changing. To tell if an object is moving, you use a reference point. If an object's distance from another object [reference point] is changing. A place or object used for comparison to determine if something is in motion.
At rest, when travelling at a constant speed, and when in mechanical equilibrium, there is no acceleration and answer choice D is correct.
<h3>How would you define acceleration?</h3>
In mechanics, acceleration describes the rate at which a driving object's velocity changes over time. They are accelerations and vector quantities. The direction of an object's acceleration is determined by the direction of the net force acting on it. Depending on whether an object is moving faster, slower, or in a different direction, its velocity may change. Examples of acceleration include a falling apple, the moon orbiting the earth, and a car that has stopped at a stop sign. The car is positively accelerating if the speed is increasing. As the car slows down, its speed decreases. A decline in speed is referred to as negative acceleration. In both situations, the car is traveling ahead, yet one has a positive acceleration and the other a negative one.
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Answer:
Explanation:
When a projectile is fired upwards with some initial speed then the it reaches the top of the projectile and then falls back to the ground.
According to the question we need to find the work done by the gravity which is acting downwards for the projectile when it is at a position just about to hit the ground in course of falling down.
As we know that work is given as:
here:
force of gravity on the object (which is acting downwards)
displacement of the object
- Here the work done by the gravity at an instant just before the projectile hits the earth will be negative as the displacement is in the direction opposite to the force of gravity.
Answer:
Phospholipids are able to form cell membranes because the phosphate group head is hydrophilic (water-loving) while the fatty acid tails are hydrophobic (water-hating)
