Christian Lawson-Perfect- Numbas at mathcentre.ac.uk

Lead developer of Numbas.

I'm happy to answer any questions - email me.

Christian's activity

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Christian Lawson-Perfect commented on Particle in vertical equilibrium, accelerating horizontally 9 years, 5 months ago

In GeoGebra, hide the points that don't need to be drawn, such as the ones on either end of the acceleration vector.

a)

Need to specify units in "the mass of the particle $K = ...$". Stick an $\mathrm{N}$ after the input to show that the answer is in Newtons. The input line should go

$C = $ [[0]] $\mathrm{N}$

b)

Use \simplify - I got $1gN$ when FD = 1. You need to say which direction to resolve the force in, or ask to find the magnitude of the force.

c)

Decelerating in which direction? You've set up a 2D problem sort of needlessly, because the components are completely independent.

Why change the mass of the particle? Say you're considering a different particle. How is this part different to part a?

d)

Again, this is the same as part b but with different numbers - maybe split this into two separate questions. And again you need to use \simplify when giving the force $B$.

The prompt should say "now there is a net force of ... acting downwards". But how do you know the net force? You'd work it out from observing the acceleration. This question could go as follows:

Set up: the particle has mass $K\, \mathrm{kg}$, and is accelerating at $a\, \mathrm{ms^{-2}}$ vertically downwards.

First part: What is the total force acting on the particle?

Second part: a downwards force of $D \, \mathrm{N}$ and a downwards force $B$ are being applied to the particle. What is the magnitude of $B$, in Newtons?

You could have one question considering vertical acceleration, and another for horizontal.