# "the force of gravity does not depend on mass"..

Discussion in 'Mathematics' started by briancant, Apr 10, 2019.

1. ### briancantOccasional commenter

On the top of page 147 of the Pearson Year 1/AS Statistics and Mechanics text book it states;

As the force of gravity does not depend on mass, this means that in a vacuum an apple and a feather would both accelerate downwards at the same rate.

What do you make of the first part of this statement?

Oh dear!

4. ### BG54New commenter

I'm sure the alert student will see that the book contradicts itself on p162, W = mg. ;-)

5. ### hert0677New commenter

In a vacuum the feather would get sucked upwards and the apple would never fit through the nozzle. Pearson haven't thought that through

Flanks and Informant like this.
6. ### afterdarkEstablished commenter

Considering what Pearson charge for their books it is a poor show.

Would you be happier if the words 'force of' were replaced by the 'acceleration due to' ?

7. ### briancantOccasional commenter

Their books have lots of errors in the answers. Perhaps given the need to create new books for the new specifications, in a short time, that is understandable.
This however is a massive conceptual error that indicates that the person who wrote it doesn't understand the topic.

8. ### afterdarkEstablished commenter

I quite agree. However I have never come across a mathematics text book that does not have at least one error. Often you can imagine that the typsetters simply did not understand if the source meant S or 5, for example.

Maybe, I am more concerned with collating a set of corrections so that can be used for future reference.

I ask students to write notes about these things or corrections in pen in books. Exedcel have a habit of producing newer corrected editions of the textbook that look almost identical to the previous run.

9. ### gainlyEstablished commenter

Dear Mr Pearson,

According to Newton's law of gravitation the gravitational force is given by:

F = (GMm)/r^2

Since gravitational force does not depend on mass, please can you explain what M and m represent in this equation.

Regards