# To stimulate a roller coaster, a cart is placed at the height of 4 m and allowed to roll from rest to the bottom. Find each of the following for the cart if friction can be ignored: a) the speed at the height of 1 m, b) the height when the speed is 3 m/s?

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Not sure how to do these without a given mass.

Not sure how to do these without a given mass.

##### 1 Answer

#### Explanation:

As it is said not to consider about frictional force,during this descent,**total energy of the system will remain conserved.**

So,when the cart was on top of the roller coaster,it was at rest,so at that height of

Now,when it will be at a height of

so,we can write,

or,

Putting,

Again,using the same equation,if you take

or,

or,

so, at