Physics Investigation of Stopping Distances

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Physics Investigation of Stopping Distances

Aim

===

To investigate how a toy car's stopping distance is affected by its

vertical height

Hypothesis

The greater an object's gravitational potential energy the longer it

will take to cease all movement. This is because it will have more

kinetic energy - and if we assume that the energy is removed at a

constant rate by friction then the more kinetic energy an object has

the longer it will continue moving

Background knowledge

This experiment will be looking at the transfer of energy from gravitational

potential energy (gpe) to kinetic energy (ke) and the effect of

friction on the loss of kinetic energy.

gpe = mass (kg) X force of gravity (9.18N per kg on Earth) X the

object's vertical height (m)

This means that the more vertical height an object gains the greater

its gpe is. Friction applies an opposite force to a moving object,

which means the object will loose energy faster than usual. The

greater the friction the faster the energy loss.

Equipment

Toy car, 2 wooden bards (1m long 40cm wide), metre ruler, several

textbooks of equal size ('physics in action'), a set of scales

Method

1. Record weight of car

2. Using the formula for gpe calculate the car's gpe

3. Set up the boards and books as seen below so that the start point

is at the required height

4. Hold car at start point and release

5. Record the distance travelled across the flat board

[IMAGE]

Fair test variables

· Same equipment for each test - different cars will perform

differently, different boards will give different amounts of friction

· Start point on board - if the car travels a different distance on

the sloped board before it runs on the flat board than it will be

affected by gravity differently and this will change the results

· The same person should release the car each time and in the same way

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