Practical 3 - Invstigation of Newton’s second law

Question 1

What does the gravitational force of the slotted masses do?

Answer 1

Causes the entire mass of the system to accelerate

Question 2

What causes he entire mass of the system to accelerate?

Answer 2

The gravitational force of the slotted masses attached via a pulley

Question 3

What makes up the entire mass of the system used?

Answer 3

Mass of rider (M)
Total mass of slotted masses (m)

Question 4

m meaning

Answer 4

Total mass of slotted masses

Question 5

M meaning

Answer 5

Mass or rider

Question 6

What’s the alternative way of writing Newton’s second law that we can use to investigate it?

Answer 6

mg = (M+m)a

Question 7

Which equation can be used to test Newton’s second law?

Answer 7

a = mg
——
(M + m)

Question 8

How can we use a = mg/(M+m) to test Newton’s second law?

Answer 8

If the total mass of system (M and m) remains constant, then the acceleration, a, should be proportional to the gravitational force, mg.

Question 9

What should be proportional in this practical and under which conditions?

Answer 9

Acceleration should be proportional to the gravitational force
(If the total mass of the system remains constant)

Question 10

What’s the first step to completing this practical?

Answer 10

Fix the thread to the rider and attach five slotted 5g masses to the other end

Question 11

What do we do after fixing the thread to the rider and attaching slotted masses to the other end?

Answer 11

Set the light gates to record the acceleration and allow the slotted masses to fall to the ground

Question 12

How do we calculate mg?

Answer 12

Mass (in kilograms) x g

Question 13

How do we calculate the acceleration in this practical?

Answer 13

It’s recorded by the light gates

Question 14

What do we do after recording the acceleration for a particular run with the masses?

Answer 14

Remove one of the slotted masses and place it on the rider (so keeping the total mass constant)

Question 15

What do we do with the masses after each run?

Answer 15

Remove one of the slotted masses and place it on the rider (the total mass of the system remains constant)

Question 16

What remains constant throughout this practical?

Answer 16

The total mass of the system

Question 17

Until when do we repeat this experiment?

Answer 17

Until all of the different accelerating masses have been removed

Question 18

How do we plot the graph for this practical and what should it show?

Answer 18

Acceleration on the y-axis
Gravitational force (mg) on the x-axis
It should be a straight line through the origin to show that they’re directly proportional

Question 19

Which part of the new way of writing Newton’s second law is used to represent the gradient?

Answer 19

1
—
(Mxm)

Question 20

How do we work out the total mass (M+m) in our system?

Answer 20

1
—. = gradient
(M+m)

(M+m) = 1
——
Gradient

Question 21

How do we work out our gradient?

Answer 21

Change in y
——————
Change in x

(From our graph)

Question 22

How do we work out our % difference between the actual mass and the mass calculated for the system?

Answer 22

Difference
————— x100
Actual

Question 23

What does the 1/(M+m) equation give us?

Answer 23

Our gradient

Question 24

What % difference between our actual value and our calculated value gives us a reliable result?

Answer 24

5% or less

Question 25

What does a 5% or less difference between our calculated mass and the actual mass mean?

Answer 25

That we have reliable results and that the experiment was a success

Question 26

Which equation is used to get the equation for the gradient and what is this?

Answer 26

a = mg
——
(M+m)

Gradient = 1
——
(M + m)

Question 27

How do we eliminate the effects of gravity?

Answer 27

Ensure that the track is level