Why is it easier to push something heavy down a hill than it is to push it across a flat, horizontal surface?

Question

Please include 2 or 3 reasons. Thanks.

Answers involving kinetic and static friction would be particularly helpful.

Answer 1

Pushing it down the hill means you have the parallel component of gravity in addition to the force you're exerting as opposed to pushing it on a flat surface in which gravity is not affect anything on the horizontal level. The force normal down a hill would also be less, meaning the force of friction will in turn also be less.

Answer 2

Geddy_V explained it mostly already:

When pushing down the hill, friction acts on the normal force to the hill, which would be less than the whole weight of the object. So there is less friction force.

Also, some of the force that gravity supplied would be pushing the object down the hill (rest is the normal force), thus helping you to overcome the force of friction, which we already showed was lessened.

So on a hill, the static friction force is lessened, and gravity provides some force down the hill to aid in your overcoming what friction there is.

Answer 3

It's a simple form of physics. if something is flat and horizontal it has about a fifty percent pull of gravity, or pull towards the center of the earth. While on a hill, the thing heavy in question most likely has great mass and is being pushed to earths core which is nearest at the bottom of the hill. The object will follow the path of least resistance and (instead of going straight through the ground and to the core) wil roll straight down a hill. on a neutral surface - a flat one - the path of least resistence is neither to the right or left and will have the same resistance no matter which way you push it. I hope I helped.

Answer 4

Gravity assist - if something is going downhill - something heavy, gravity is only on the area equal to the new dimension of the base. Think of it like this, a box flat on the ground is 2 feet long, at a 45 degree angle, measure the vertical footprint now - shorter. This is less kinetic friction.

Answer 5

Potential energy. Getting the boulder up the hill in the first place gave it potential energy. This is released (converted to kinetic energy) as gravity pulls it downwards again, helping you with the pushing. And this is why it's so much harder to push it back up that damn hill - because you are actually giving additional energy that can't be released until you push it down again.

Answer 6

One factor is friction. Friction is a function of the weight of the object, and resists you pushing the object. Gravity pulls down along the incline angle, helping you defeat friction force that keeps the object from moving

Answer 7

The main reason it's easier going down hill is that gravity is helping pull while you push.

Answer 8

If it's a dead body, roll it up in a big piece of carpet (preferably red). take it to the ocean. get a boat , go out a few miles. put a chain around your dead friends waist. Tie 3 big cinder blocks to this chain with heavy wire. ( put some fresh fish guts in your pals clothes, or just stick the body again with that big knife you have, that will make the blood flow again !). throw the body overboard, it will sink right way due to GRAVITY. Ask Scott Petersen in San Quentin, but he wasn't very good at it. But , why would you want to push a body around anyway? also take in to account the Zodiac possibility.

Answer 9

It's easier because the force of gravity (32 ft/ sec^2) helps pull the objcet closer to the center of mass of the Earth.

Answer 10

you can say it has to deal with gravity
but also weight
the heavier the object it will be more likely to go down the hill
since such thing can be greater than gravity
think of dropping a heavy book
on a hoizontal surface it is evenly forcing on eachother
so its harder to push across the surface