Derive an expression for the time taken, (t) for a test mass to fall to the ground from a height (h) in a uniform gravitational field (g = 9.81 ms^-2)

We first build an intuition for exactly what acceleration is and what we expect to happen. In the uniform gravitational field approximation, we assume h to be much less than the radius of the Earth. Therefore, the higher we drop the test mass from, the larger the velocity of the test mass when it hits the ground at h = 0. Derivation: We take velocity = dh/dt = acceleration(g)*time(t), and then use the required calculus to integrate to find the expression: h = (1/2)gt^2 . We finally tidy this up by rearranging using basic algebra to express t as a function of h t(h) = SQRT(2h/g) (I would then very likely ask to plot that function so that the intuitions developed at the start can be solidified and we can gain some confidence in the use of calculus to solve real problems.) 

CB
Answered by Charlie B. Physics tutor

2008 Views

See similar Physics A Level tutors

Related Physics A Level answers

All answers ▸

A car is travelling at 10m/s when it brakes and decelerates at 2ms^-2 to a stop. How long does the car take to stop?


When catching a ball, a cricketer moves his hands for a short distance in the direction of travel of the ball as it makes contact with his hands. Explain why this technique results in less force being exerted on the cricketer's hands


Outline the principal features of a geostationary orbit and use them to explain one use of satellites in this type of orbit.


How can I measure the orbital period of a satellite around Earth?


We're here to help

contact us iconContact ustelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

MyTutor is part of the IXL family of brands:

© 2025 by IXL Learning