Glossary of Keywords
Vector quantity – refers to the measure of both the magnitude (size) of the medium and the direction taken by the medium.
P.E – symbol for Potential Energy. SI unit is Joules (J). Elastic potential energy refers to the stored energy in an elastic band.
L – length of the elastic band upon stretching. SI unit: meter (m)
K – spring constant
SI unit – means System International of physical units.
K.E – Kinetic Energy, SI unit is Joules (J). Kinetic energy is the motion energy that results when an elastic band gets stretched.
M – mass, SI unit is Kilograms (Kg).
V -velocity. SI unit: meter per second (m/s)
W.D. – work done. SI unit: Newton-meter (Nm)
a – acceleration. SI unit: meter per squared second (m/s²)
u – initial velocity. SI unit: meter per second (m/s)
t – time. SI unit: seconds (s)
F – force. SI unit: Newton (N). Force is the push or pull.
d.p – decimal places
s – displacement. SI unit: meter (m). Displacement is a vector quantity which shows how far an object from a given point.
Atmospheric pressure refers to the pressure exerted as a result of the weight of the atmosphere. The SI unit for atmospheric pressure is Pascals (Pa).
Matter refers to anything which occupies space and has weight. There are three states of matter; solid, liquid and the gaseous state.
1. False. Velocity and acceleration are vector quantities which are affected by magnitude and direction. As the medical supply trolley wheeled around a curved pathway, there could be a change in direction, and as a result, its velocity and acceleration changed. The trolley had to slow down, decelerate, so as go around the curved pathway.
False. In the process of stretching the elastic band around the arm of the patient to serve as a tourniquet, potential energy usually stored in the rubber changes into kinetic energy. The stored energy in the elastic is called elastic potential energy and is equivalent to the product of half times the length of the elastic band stretch and the spring constant.
P.E= 1/2L²×K
Since the band stretches on the arm of the patient, motion energy can be calculated by multiplying the elastic band squared velocity with one-half its mass.
K.E = 1/2MV²
Joules is the SI unit symbol for both elastic potential energy and kinetic energy. In this instance, there is work done since there is the change in kinetic energy of the elastic band that stretches around the arm of the patient. There is a strong relationship that exists between work done and the amount of change in energy as shown in the equation below;
W.D. = 1/2MV²
2. In this circumstance, the student will choose to move the box into the shelf through the straight line so as to make her work easier. An illustration diagrammatically showing how the student will push the box is as shown below.
Information gathered from the question;
Mass of the box = 12 kg
True or False Statements
u = 0.15 m/s
t = 2.0 s
the distance of door ahead of the box = 1.0 m
In this case, the student healthcare professional chose to move through the hypotenuse so as to make the work easier. The length of the hypotenuse gets calculated by applying Pythagorean theorem, which states that the side opposite of the right angle is equivalent to the total
summation of the squares of the two sides forming the right angle (Posamentier, 2010). Thus,
c² = a² + b²
c² = (0.3) ² + (5.5) ²
c² = 30.34
Finding the square root of 30.34;
√c² = √30.34
c = 5.508175741568165
giving the answer into 4 d.p;
c = 5.5082m
5.5082 m, is the distance the student healthcare professional will cover to move the box onto the shelf.
For the student to stop within the 2.0 second, he/she would have applied some force so as to decelerate. Rate of deceleration applied for the student to stop is calculated as follows;
a = (v- u)/t
= (0 – 0.15) ÷ 2.0
= – 0.15 ÷ 2.0
= – 0.075 m/s²
When the acceleration answer is negative into shows deceleration, thus,
deceleration rate =0.075 m/s²
The force applied for the to stop is calculated through applying Newton’s second law of motion. The law states that; the rate at which the momentum of a body changes, is proportionately direct to the force applied given that the change in momentum occurs in the same direction to that of the force applied (Chiang, 2011). The law can also, in simpler terms refer to the force acting on a body being equivalent to the mass of the body multiplied by the body’s acceleration. Hence;
F = ma
= 12 × 0.075
= 0.09 N
To determine whether the student healthcare professional would avoid a collision or not, will have to calculate the displacement of the box, that is, the distance in a specified direction. If the displacement is less than one meter, then definitely the student would avoid a collision. Displacement gets calculated by applying Newton’s second equation of motion;
s = ut + (1/2)at²
= (0.15 × 2.0) + (1/2 × (- 0.075) × 2²)
= 0.30 + (- 0.15)
= 0.30 – 0.15
= 0.15m
Since the displacement is equal to 0.15 m it is therefore evident that the student would avoid the collision with the door being opened by another student.
3.
1. The soft drink represents the liquid state of matter, in which the liquid particles are far apart. The liquid particles freely circulate within the defined positions. The liquid takes up the shape of the container. The plastic bottle represents the solid state of matter, in which the solid particles are closely packed together to form the shape of the container, the solid particles do not circulate with their fixed positions.
2. The flow of the fluid did not commence immediately but remained intact until the time when the lid got opened. Upon the removal of the lid that was covering the fluid, pressure differences between the inside and outside of the bottle arose. In the beginning, the pressure exerted by liquid molecules of the soft drink on the walls of the plastic bottle from the inside balanced the atmospheric pressure acting on the outside of the plastic bottle, small hole, and the lid surface. Upon removal of the lid, the atmospheric pressure that exerts on the fluid surface and the outside of the bottle exceeded the inside pressure exerted by the liquid molecules of the soft drink. Since the atmospheric pressure from the outside was greater than the inside liquid molecules pressure; the fluid was forced to flow through the small hole.
References:
Chiang, M. (2011). Isaac Newton and his laws of motion (1st ed.). Pelham, NY: Benchmark Education Co.
Posamentier, A. (2010). The Pythagorean theorem (1st ed.). Amherst, N.Y.: Prometheus Books.