# Can anything have an acceleration in the opposite direction to its velocity? Essay

Custom Student Mr. Teacher ENG 1001-04 6 November 2016

## Can anything have an acceleration in the opposite direction to its velocity?

Yes, since acceleration has two components: velocity and direction. There are three instances when acceleration can happen: first, there is constant velocity but a change in direction; second, there is changing velocity but same direction; and third, both the velocity and the direction are changing. In this case, acceleration happens in such a manner that the velocity is increasing with the direction changed. A very simple example would be the projectile of a ball thrown from the top of a building. While the ball falls down, its velocity is increasing, and its direction is going down (meaning, negative).

Another example would be phone which slides down the stairs. As it goes down, its velocity is increasing while its direction is going downwards. 2. (Free Fall) Can anything ever have a downward acceleration greater than g? If so, how can this be accomplished? Yes, it is possible that a downward acceleration is greater than g (acceleration due to gravity which is -9. 8 m/s2). In the concept of free fall where air friction is neglected, the acceleration becomes zero, which means that the downward velocity of the falling object is constant in time. 3. (Mass and Weight) Consider the statement: Sara weighs 55kg.

What is wrong with the statement? Give two ways to correct it. Mass is different from weight. By equation, weight is equal to mass (m) multiplied with acceleration due to gravity (g). Although the quantity is correctly placed with its unit wherein kilogram is a unit of mass, the word “weigh” does not suit the statement with respect to the equation mentioned. It could be revised as: (1) Sara’s mass is 55 kg, or (2) Sara weighs 539 Newtons. In the second revision, the weight becomes 550 Newtons or kg-m/s2 from the multiplied values of mass (55 kg) and acceleration due to gravity (9.

8 m/s2). 4. (Third law of motion) Two children wish to break a string. Are they more likely to succeed if each takes one end of the string and they pull against each other, or if they tie one end of the string to a tree and both pull on the free end? Why? The second option is more likely to succeed. Considering Newton’s Third Law of Motion where it states that in every action, there is an equal and opposite reaction, it is most possible that if they employ the first choice, they would have a difficulty in breaking the string.

This is because if both children exert equal forces towards opposite directions, the result would be that the forces will cancel. In the event where the other end of the string is tied to a tree, (horizontal) tensional force may be exerted by the children which, this time, is twice the value – meaning, a stronger force. The tree does not exert an opposite horizontal force, therefore allowing for the breakage of the string. 5. (Newton’s law of gravity) Compare the weight and mass of an object at the earth’s surface with what they would be at an altitude of two earth’s radii.

Mass and weight on the surface of the earth will be bigger than outside the earth’s surface (or at an altitude equal to twice of the earth’s radius). This is because the force of gravity is stronger on earth. The gravitational pull from the center of the earth will be stronger on the nearer surface than on an altitude which is greater in distance with respect to the center of the gravitational pull. This could be illustrated by man’s capacity to stay in place and not fall on normal earth surface situation as opposed to the “floating” capacity of astronauts in space, where the gravitational force is much lesser.

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• University/College: University of Chicago

• Type of paper: Thesis/Dissertation Chapter

• Date: 6 November 2016

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