the force due to gravity on venus is 8.9 m/s. would a 5.0 kg cantaloupe weigh more on earth or venus ?

Answer 1

Hi Storm,

Here is an answer with an explanation for your question. Please try to not only know the answer but to understand it.

First - "Gravity" is expressed as "the acceleration due to gravity". It is 9.8 m/s² on earth and 8.9 m/s²on Venus.

Second - Weight is a force. It is the the "force due to gravity" on an object.

Third - Force and acceleration are directly proportional. This is from Newton's Law ∑F=ma.

Therefore, as the acceleration due to gravity increases the weight (or force due to gravity) also increases, and as the acceleration decreases the force also decreases.

Since the acceleration due to gravity on Venus is less than on Earth, the force, or weight, is less on Venus than on Earth for an object. A 5 kg cantaloupe weighs less on Venus than on Earth.

I would like to point out a couple errors you made in your question. Understanding what they are is important to understanding the details of the physics you are studying.

You said "The force due to gravity on Mars is 8.9 m/s."

It is not a force that you have given. It is the acceleration due to gravity, or the acceleration caused by gravity. Remember that "due to" means "caused by". The force due to gravity is the weight of an object.

Because it is an acceleration the units are m/s² (8.9 m/s² or 8.9 m/s/s -meters per second squared or meters per second per second). The units m/s that you gave indicate a speed or velocity, not an acceleration.

Always be careful to use the right word and the right units. Science is very exact - unlike English - words and units have only one meaning. There are no multiple meanings for words in science.

Using the wrong word or the wrong units on a science test will cause your answer to be wrong and you will not get the best grade.

In addition remember that it is - 'acceleration caused by gravity' or 'acceleration due to gravity'. It is NOT 'acceleration OF gravity'. Gravity is not an acceleration (ft/s² or m/s²). Gravity is a force (pounds or newtons). The force (in this case gravity) causes the acceleration (in this case the acceleration due to gravity).

Answer 2

Please not that force has units of N, so the force due to gravity on Venus cannot have units of m/s (those are units for velocity)

Actually, the acceleration due to gravity on Venus is 8.9 m/s². The acceleration due to gravity on Earth is 9.8 m/s².

In order to find weight we need to use the following equation:

Weight = mg (mass x gravity)

They gave a mass of 5.0 kg. Mass does not change regardless of what planet it is on. Weight changes due to the different gravities though.

On Venus:

Weight = (5.0)(8.9) = 45 N (Note that our answer should only have 2 significant figures)

On Earth:

Weight = (5.0)(9.8) = 49 N

Therefore, the cantaloupe weighs more on Earth FINAL ANSWER

*Note, we could have answered that it weighed more on earth simply by recognizing that the acceleration due to gravity on earth is greater than that of Venus, but I wanted to also explain by calculating each of the weights to verify this for you.