RP7 Acceleration

Question 1

(effect of force, constant mass) outline the basic steps of the practical.

Answer 1

1. mark out 20 cm intervals on a bench using a ruler
2. attach a string to the trolley, and pass it over a pulley at the end of the bench
3. attach varying masses to the end of the string
4. time how long it takes to reach each interval

Question 2

(effect of force, constant mass) suggest a method for marking out 20cm intervals on the desk.

Answer 2

place pieces of tape every 20cm from the starting point of the trolley. use a metre rule to measure each interval.

Question 3

(effect of force, constant mass) what piece of equipment is used to record the times?

Answer 3

a stopwatch with the ability to record multiple times (laps) so you can record when it passes each interval.

Question 4

(effect of force, constant mass) what safety precaution should be taken when releasing the masses?

Answer 4

ensure you are not standing underneath where they are hanging. a padded bucket could be place underneath them to catch them when they drop.

Question 5

(effect of force, constant mass) how would you expect the acceleration of the trolley to change as you add more weights to the end of the spring?

Answer 5

the more weights that are added, the greater the force that is accelerating the trolley and so the greater the acceleration.

Question 6

(effect of force, constant mass) which of Newton’s laws explains the relationship between force and acceleration?

Answer 6

newton’s second law
force = mass x acceleration

Question 7

(effect of mass, constant force) how can you choose an appropriate quantity of masses to use as the fixed mass for this experiment?

Answer 7

carry out a preliminary experiment to find what weight is needed to just accelerate the trolley from rest.

Question 8

(effect of mass, constant force) outline the basic steps of the practical.

Answer 8

1. mark out 20 cm intervals on a bench
2. attach a string to the trolley, and pass it over a pulley at the end of the bench
3. attach a fixed mass to the end of the string and release it so the trolley accelerates
4. time how long it takes to reach each interval
5. repeat with varying masses attached to the trolley

Question 9

(effect of mass, constant force) what would be the consequence of using too large a fixed weight?

Answer 9

the trolley would accelerate too quickly for the timing at each interval to be accurate.

Question 10

(effect of mass, constant force) how would you expect the acceleration of the trolley to change when you add masses onto the trolley?

Answer 10

the acceleration will decrease s masses are added to the trolley, because a = F/m

Question 11

(effect of mass, constant force) suggest a way that the experiment could be changed to improve the timing of the trolley at each interval.

Answer 11

a video camera could be used to record the experiment and then timings taken from the slowed down video afterwards. this reduces uncertainty from human reaction times. alternatively, light gates could be used.