Log in

View Full Version : A hammer falling


spencer edward
Jan 8, 2009, 03:23 PM
This question is like a projectile motion problem but it is not

The question says a hammer falls off a angled roof and wants to know how far from the house will it land

I know how to do projectile motion problems when the object is thrown but not dropped

I don't know if I am supposed to use the same formulas or different ones. Please help me to get it started

ebaines
Jan 8, 2009, 03:32 PM
Does the question provide additional data that would allow you to calculate the horizontal and vertical components for the hammer the instant it slides off the roof? That would then allow you to use the standard equations for a free-falling object. Another thingto watch out for - remember that the equations of motion apply to the center of gravity of an object, so depending on how they'e posed the question you may have to take that into account.

spencer edward
Jan 8, 2009, 03:48 PM
It does tell me the initial velocity as it slides off the roof

Okay they didn't put anything trickey in the question

And how can I use the formula of a free falling object
When basically the object was thrown downwards at an angle.

They also did not give me time is it possible to solve this without time?

letmetellu
Jan 8, 2009, 05:45 PM
Does the pitch of the roof have any affect on the distance the hammer will travel or does the higher pitch just make the hammer get to the ground faster.

spencer edward
Jan 8, 2009, 06:05 PM
Does the pitch of the roof have any affect on the distance the hammer will travel or does the higher pitch just make the hammer get to the ground faster.

Umm what do mean by pitch
It slides off the roof

The question is a man drops a hammer onto the roof which is at a 32˚ to the horizon
The hammer starts to slide and falls off the roof at a velocity of 9.42 m/s. the roof is 17.1 meters off the ground.
How far from the house will the hammer land

Oh and the hammer is .38 kg

ebaines
Jan 9, 2009, 05:59 AM
Form this data the initial horizontal and vertical components of velocity as the hammer slides off the roof are respctively:


V_h = 9.422 m/s \cdot cos (32 \deg) \\
V_v= -9.422 m/s \cdot sin(32 \deg) \\


To figure the time it takes to hit the ground the equation


d = \frac 1 2 a t^2 + V_v t + d_0


Where a = -g and d_0 = 17.1m.

Can you take it from here?