Physics Assignment 1: Solutions for MEDI11002, Term 1, 2020, Uni

This document presents a comprehensive solution to a physics assignment (MEDI11002) for health sciences students. It begins with a glossary defining key terms like mass, volume, density, force, and acceleration. The assignment addresses two main questions. The first question examines the relationship between volume, mass, and density, determining the validity of statements regarding these concepts. The second question involves applying Newton's second law to calculate the force exerted on a ball during a collision, considering the mass, velocity, and time of impact. The solution provides detailed explanations, equations, and calculations, referencing relevant physics principles and concepts. The assignment follows a structured approach, identifying knowns, unknowns, and relationships to arrive at the final answers. References to physics textbooks and research papers are included, providing supporting information for the solutions.

SOLUTIONS TO PHYSICS QUESTIONS MEDI11002
Name of student
Institution affiliation
Date
MEDI11002 / Term 1 / 2020

GLOSSARY
Mass - The amount of matter in a substance.
Volume – “The quantity of space occupied by a substance.”
Density – “The mass per unit volume of a substance.”
Solids – “The phase of matter characterised by a definite volume and shape”.
Force – “Refers to a push or pull on an object. It is a vector quantity whose SI unit is
Newtons.”
Net Force – This is the resultant force after combination of all the forces that act on a
substance.1
Acceleration – “The rate of change of velocity”.
“Newton’s second law of motion” – “The acceleration produced by a net force on an object is
directly proportional to the magnitude of the net force, is in the same direction as the net
force, and is inversely proportional to the mass of the object”.
Velocity – “The speed of an object and its direction of motion; a vector quantity”.
D−Density
m−mass
v−volume
v1 −initial velocity
v2−Final velocity
a−acceleration
F−Force
∆ v−change ∈velocity
m1−mass of object 1
m 2−mass of object 2
MEDI11002 / Term 1 / 2020

Question 1 (A)
If two different solids have the same volume, they must also have the same mass.
This statement is false. Different objects have different densities. Density is such that it is
directly proportional to the mass of an object and inversely proportional to its volume.
D= m
v … … … . … … …… … Density Equation
m=D × v … … … … … … … .. Mass Equation
From the density equation, density refers to the mass of an object by its volume. Mass refers
to the quantity of matter in a substance while volume is how much space an object occupies.
From the mass equation, mass is equivalent to the product of density and volume of an object.
The differences in the masses of substances with the same volume is brought about by
differences in densities of the substances.2 Therefore, with this case two solids that have the
same volume may not have the same mass due to varying density of the substances.
Question 1: (B)
Using the equation F=m*a, if m = 3.50Kg and a = 2m/s2, then the product of 3.50 multiplied
by 2 equals 7N
True, the statement is correct. The resultant force that acts on a substance is determined by
the product of the mass of the substance and its acceleration, according to Newton’s second
law of motion. With the increase in the force acting on an object there is a corresponding
increase in the acceleration.3 A substance with a bigger mass needs a force of higher
magnitude for it to move at the same acceleration of an object with relatively small mass.
Therefore, given a mass and the acceleration, the required force to cause such an acceleration
MEDI11002 / Term 1 / 2020

can be determined by multiplying the mass in Kilograms and acceleration in m/s2 to get the
force in Newtons(N), since 1 kgm/s2 is equivalent to 1 Newton.
Question 2
A ball of mass 2kg is set in a straight-line motion. It strikes a second, stationary ball of mass
5kg. The velocity of the first ball, when it strikes the second ball is 20m/s. The first ball
comes to a complete halt as a result of the collision. The two balls are in contact for 0.01
seconds.
Calculate the force applied to the second ball by the first ball.
Known Items.
Mass of the first ball (m1) = 2kg
Mass of the first ball (m2) = 5kg.
Initial velocity of m1=20 m/ s
Final velocity of m 1=0 m/s
Time ( t ) =0.01 s
The magnitude of Force of an object can be determined by multiplying the acceleration by
the mass of the object. Acceleration can be determined by finding out the rate at which the
velocity of the ball changes.
The ball is travelling in a straight line, and its final velocity is 0 m/s from an initial velocity
of 20 m/s. The change in velocity is such that it is directly proportional to elapsed time.
Acceleration is calculated as follows. Determining the difference between final and initial
velocity and dividing by time.
Identifying the variable, we are solving for:
MEDI11002 / Term 1 / 2020

Looking to solve the total force (F) applied to the second ball by the first ball
SI units of Force is Newtons (N)
Significant Digits 2.
Identify concepts and relationships for the identified variables:
Force causes the changes in the state of motion of an object measured in Newtons (N)
Force is proportional to acceleration = a α F. 4
Relationship:
∆ v=v2−v1
a= ∆ v
∆ t
F=ma
Substituting and Solving:
a= v2−v1
t = 0−20
0.01 =−2000 m/s2
F=m1 × a=2 kg ×−2000 m/ s2
F=−4000 N
Calculating the force using acceleration and mass. Mass of the first ball is 2kg and the
acceleration of the object is -2000 m/s2 Therefore, the total force applied to the second ball by
the first ball converting to the correct newtons is -4000 N then changing to the correct
significant digits of 2 the total force is 4.0 x 103 N
Final Answer:
The final force applied to the second ball after being hit by the first ball is 4.0 x 103 N.
MEDI11002 / Term 1 / 2020

References
1. Hewitt PG. Conceptual Physics. 12th ed. M.U.A: Pearson Education; 2015.
2. The Laws of Motion from Newton to Kant. Kant on Laws. 2019:89–117.
3. Mitsuhashi K, Nakamura M, Chiba M, Hashimoto H. Suggestion of Motion
Velocity/Acceleration Curved Surface. Proceedings of the 14th International
Conference on Informatics in Control, Automation and Robotics. 2017;
4. Trisnowati E, Sumardi Y. Developing the student worksheet with problem-solving
approach to improve critical thinking skills and the concept understanding of physics.
Momentum: Physics Education Journal. 2019:32–41.
MEDI11002 / Term 1 / 2020

MEDI11002 / Term 1 / 2020