A child is standing on a walkway that is moving at 2 metres per second and decides to turn around and walk back to the start at 2 metres per second. Explain why the child cannot reach the start of the walkway at this speed.

Assuming that the walkway is moving in a positive direction, the child is walking in the opposite direction to it and is therefore walking in the negative direction. Both the child and the walkway have velocity, but their velocities are opposite since the direction they are moving in are directly opposite to eachother, however since they are moving at the same speed, the velocities will cancel out: -2+2=0. This result shows that in fact the child will not actually move and seem to be walking on the spot. 

MS

Related Physics A Level answers

All answers ▸

State similarity and difference between the electric field lines and the gravitational field lines around an isolated positively charged metal sphere.


A ball is hit horizontally at a height of 1.2 m and travels a horizontal distance of 5.0 m before reaching the ground. The ball is at rest when hit. Calculate the initial horizontal velocity given to the ball when it was hit.


What is damping in Simple Harmonic Motion?


A student is measuring the acceleration due to gravity, g. They drop a piece of card from rest, from a vertical height of 0.75m above a light gate. The light gate measures the card's speed as it passes to be 3.84 m/s. Calculate an estimate for g.