Friction

A car’s minimum braking distance is measured on a dry road surface. The same test is then carried out again on a wet road. What happens to the braking distance and to the frictional force between the tyres and the road?

May/June 2018

A force pushes a box up a rough slope. The diagram labels 4 forces acting on the box. Which of these forces is the frictional force on the box?

May/June 2019

The stopping distance of a car is made up of the thinking distance plus the braking distance. Which factors influence the braking distance?

May/June 2023

A box is pushed up a rough incline from X to Y. The diagram indicates four forces acting on the box. Which of these forces is the frictional force on the box?

May/June 2024

In which example does friction act in the same direction as the object's forward motion?

Oct/Nov 2015

A car is moving forwards at high speed. The brakes are applied, and the car skids over the road surface. In what direction, and at what point, does the friction force act?

Oct/Nov 2020

What makes the frictional effects experienced by a cyclist increase?

Oct/Nov 2022

A car is moving along a straight road at $60\,\text{km h}^{-1}$. The road surface is dry. The driver then brakes sharply. The table gives the thinking distance, the braking distance and the stopping distance. The same car, driven by the same driver at $60\,\text{km h}^{-1}$ on the same road, is now on a wet surface. Once again, the driver brakes sharply. What effect does the wet road have on the thinking distance, the braking distance and the stopping distance?

Oct/Nov 2022

A car’s stopping distance at a given speed is recorded under four conditions: on a dry road with new tyres; on a dry road with old, worn tyres; on a wet road with new tyres; on a wet road with old, worn tyres. The outcomes are shown. Which two outcomes could be the measurements for the dry road with old, worn tyres?

Oct/Nov 2023

When a cyclist applies the brakes on a bicycle, energy is transferred from the kinetic store to the thermal store. What is the cause of this energy transfer?

Oct/Nov 2024