In some SUVAT questions, they ask for 2 time solutions and I can only find 1. What am I missing?

Let's say we are trying to work out how long it will take for a ball to be caught after it has been thrown straight upwards. If we set the final displacement to be zero (S=0) and solve S=UT+0.5AT2, it appears that we only get one value for T. However, there will always be a step in your workings when you can cancel a T from both sides of the equation, for example: 5T2 = 100T can be simplified to 5T = 100. In this step, we miss out a solution that T=0! This corresponds to when the ball is just about to be thrown so is still in our hands (hence we have a solution for zero displacement!)

CI

Related Physics A Level answers

All answers ▸

Derive an expression for wave speed in terms of wavelength and frequency.


Using Fermat's Principle explain why it makes sense for light be refracted when crossing from one medium into another that has a different refractive index.


Asteroid of mass 10^16 kg is travelling in the equatorial plane of Earth. It hits the surface at 45°. After the impact the day shortens by 1% (15 mins). How fast was the asteroid - comment? Neglect effects of atmosphere. Consider only inelastic collision.


One of the decays of potassium (A=40, Z=19) results in an excited argon atom with excess energy of 1.50 Mev. In order to be stable, it emits a gamma photon. What frequency and wavelength has this gamma photon?