Question Constellation Sign up for free AQA · GCSE · Physics · Higher
Friction and Resultant Force
The child pushed the baby walker from a carpet onto a hard floor. The child applied the same horizontal force to the baby walker.
Explain why the speed of the baby walker increased.
Write your answer first. You can study the marking guidance whenever you need it.
Study the marking See what earns credit and compare it with a full-mark answer.
Marking points
- 1 States that the resistive force or friction decreased on the hard floor.
- 2 Links this to a larger resultant force.
Full-mark answer
The hard floor produces a smaller resistive force than the carpet. Because the child's applied force stays the same, the resultant forward force is larger, so the walker accelerates and its speed increases.
Why this answer loses marks
There is less friction on the hard floor.
That earns the first point, but the speed change needs the further link to a larger resultant force and acceleration for the same walker.