REQUIRED PRACTICAL: NEWTON'S 2ND LAW INVESTIGATION

Question 1

State the equation that links force, mass and acceleration

Answer 1

force = mass x acceleration

Question 2

What happens to acceleration if the mass of an object is doubled?

Answer 2

the acceleration will halve

Question 3

What happens to acceleration if the force is doubled?

Answer 3

the acceleration will doubles

Question 4

What is the total mass made up of?

Answer 4

the hanger and slotted masses (which provides the force) as well as the mass of the trolley itself

Question 5

What are the masses removed from the hanger transferred to the trolley when we are investigating the effect of force on acceleration?

Answer 5

we want to keep the mass of the system the same, so we cannot remove masses from the system

Question 6

What causes the force on the trolley?

Answer 6

the force of gravity acts on the masses and pulls them downwards. This force acts on the trolleys through tension in the string

Question 7

Why do we use the light gates and the data logger? What are the benefits of using data logger?

Answer 7

• the acceleration is calculated automatically reducing errors + recorded so no results are missed
• the light gates can take far more accurate readings than if you used a stopwatch
• acceleration can be measured to 3 d.p

Question 8

Sources of possible errors are:

Answer 8

• there is friction between the trolley and the desk which has not been accounted for
• there could be some air resistance which has not been accounted for
• its important that the string is long enough to keep the trolley acceleration until it has passed through both light gates

Question 9

What are we doing in experiment 1?

Answer 9

it invest how force affects acceleration

so we need to keep the mass the same in the system and change the force to see how this affects the acceleration and use Newton’s 2nd Law to find the mass of the trolley and slotted masses

Question 10

Name the independent, dependent and control variable

Answer 10

independent variable: the force

dependent variable: the acceleration

control variable: the mass

total mass of trolley and masses: measure this using a balance

Question 11

What will the gradient of this graph tell use?

Answer 11

the mass of the trolley

Question 12

Does it match with the mass of the trolley used to collect the primary data? How can we account for any differences?

Answer 12

• the value we calculated for the mass was higher than the actual mass
• this is because we did not account for friction or air resistance when we collected our data
• this means that the results for acceleration were not as high as they should have been this makes it seems like the trolley has more mass than it actually does

Question 13

What conclusion can be made from you graph?

Answer 13

• THIS IS MODEL TO WHEN ANSWERING QUESTION LIKE THIS*
• the shape of our graph is a straight line through the origin
• it shows that the acceleration of the trolley is directly proportional to the force applied
• when the force doubles from 2N to 4N the acceleration will double from 1.92 to 4.18

Question 14

What are we doing in experiment 2?

Answer 14

it invest how mass affects acceleration

so we need to keep the force the same in the system and change the mass to see how this affects the acceleration

Question 15

What conclusions can you make from the graph?

Answer 15

• the shape of the graph is a curve which shows the acceleration of the trolley is approximately inversely proportional to the force applied
• so when the force double from 2N to 4N the acceleration will almost halve from 1.7 to 0.98
• this is more experimental proof that Newton’s Second Law is true