Download LAB – NEWTON`S SECOND LAW

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LAB – NEWTON’S SECOND LAW
You know that an unbalanced force causes objects to accelerate (and an acceleration is either speeding up,
slowing down, or changing direction). You also know that inertia is a name for the tendency of objects to keep
doing what they are already doing. In addition, you also know that the more mass an object has, the more
inertia it has, and vice versa. There is a relationship between unbalanced forces, accelerations, and mass. Your
task in this lab is to discover the relationship.
Problem:
What is the relationship between unbalanced force, acceleration and mass?
Procedure:
• Use the ruler to exert an unbalanced force on either a Ping-Pong ball or a Golf Ball. You can do this by
holding the ruler in one hand and pulling one end back. When you let go, the ruler will fly forward and hit one of
the balls, exerting a force on it.
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How could you change the unbalanced force on the ball?
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How could you change the mass of the object?
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How could you measure the acceleration of the ball?
Experiment 1: The Effect of Mass on Acceleration
on
1. Briefly describe your procedure for how changing the mass changes the acceleration.
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2. When you keep the unbalanced force the same and increase the mass, how does the acceleration change?
3. When you keep the unbalanced force the same and decrease the mass, how does the acceleration change?
Experiment 2: The Effect of Force on Acceleration
4. Briefly describe your procedure for how changing the unbalanced force changes the acceleration.
5. When you keep the mass the same and increase the unbalanced force, how does the acceleration change?
6. When you keep the mass the same and decrease the unbalanced force, how does the acceleration change?
Final Challenge
7. Try to arrange things so that the golf ball and the Ping-Pong ball end up with about the same acceleration.
How will you have to alter the unbalanced force applied by the ruler to accomplish this?
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Class:_______
Newton’ s Second Law of Motion (The Law of Force)
Newton’s second law is also called the law of force. The law basically describes the relationship
between the acceleration of an object, its mass, and all the forces acting on it. It can be summarized
by the following statement and equation:
An object’s acceleration depends on its mass and the net force acting on it.
Fnet = ma
This law states that the net force acting on an object causes the object to accelerate in the same
direction of the net force. To calculate the acceleration of an object, you need to know the object’s mass
(in kilograms), the net force acting on it (in newtons), and use the equation below.
Net force (N) =
mass (kg)
Acceleration (m/s2)
According to the equation, applying a larger net force to an object results in a larger acceleration. This
is because acceleration and force change in the same way. The equation also shows that if you apply
the same force to two objects, the one with the smaller mass will accelerate more. This is because
acceleration and mass change in the opposite way.
In the same way, if you want to cause two different objects to have the same acceleration, the
object with the greater mass will require a greater force.
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Class:_______
REVIEW - NEWTON’S 1st and 2nd LAWS OF MOTION
1. For an unmoving object to start moving a(n)
has to act on it.
2. Restate Newton’s first law of motion.
3. What is inertia?
4. The amount of inertia an object has depends on its
.
5. Restate Newton’s second law of motion.
6. Write the equation that describes the relationship among an object’s force, mass and acceleration.
7. According to the equation, what are two ways to increase the acceleration of an object?
8. Fill in the missing information in the table below:
Net Force
10 N
20 N
10 N
Mass
2 kg
4 kg
1 kg
Acceleration
5 m/s2
10 m/s2
9. Describe how these variables are related to one another!! Complete the statements using the terms
increases, decreases, directly proportional and inversely proportional.
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As force __________, acceleration __________. As force__________, acceleration __________.
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As mass __________, acceleration __________. As mass __________, acceleration __________.
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Force and acceleration ARE _____________________________________.
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Mass and acceleration ARE ______________________________________.