# help with physics prob please

#### mcatgeek

some one can help me with this problem;
an object is droped from a height of h and hits ground with a velocity of 2h which of the following represents its velocity when it hits ground?
1)v
2)1.4v
3)2v
4)4v

use v=sqrt of 2gh

#### mcatgeek

can see from this problem that mcat makes you think very critically

#### UCB05

some one can help me with this problem;
an object is droped from a height of h and hits ground with a velocity of 2h which of the following represents its velocity when it hits ground?
1)v
2)1.4v
3)2v
4)4v

use v=sqrt of 2gh
Thinking critically has nothing to do with it if the problem does not make any sense. The object cannot have a velocity of 2h if you previously define h as a distance, not speed, value. You cannot find the velocity of an object on impact in terms of v if you don't define what v is, unless you mean specifically that "use v=sqrt of 2gh" means v is represented as (2gh)^1/2, in which case for an object dropped from height h with 0 initial velocity, it will hit the ground at (2gh)^1/2 and the answer would be "v". Perhaps if you could clarify..

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#### loveoforganic

##### -Account Deactivated-
10+ Year Member
thank god it doesn't make sense to someone else.

#### lorenzomicron

some one can help me with this problem;
an object is droped from a height of h and hits ground with a velocity of 2h which of the following represents its velocity when it hits ground?
1)v
2)1.4v
3)2v
4)4v

use v=sqrt of 2gh
OP, did you post the problem correctly?

#### mcatgeek

An object is dropped from a height h and strikes the ground with a velocity v. If the object is dropped from a height of 2h, which of the following represents its velocity when it strikes the ground?
A)v
b)1.4v
c)2v
d)4v

#### UCB05

An object is dropped from a height h and strikes the ground with a velocity v. If the object is dropped from a height of 2h, which of the following represents its velocity when it strikes the ground?
A)v
b)1.4v
c)2v
d)4v
"If the object is dropped from" is significantly different from "hits ground with a velocity of" =P

In that case since v=sqrt(2gh), the new velocity will be v'=sqrt(2g2h), or v'=sqrt(2)sqrt(2gh) ~= 1.4v