If I were at the top of the Empire State Building and threw a penny over the edge...?

Question

how long would it take for the penny to reach the ground? AND
If the penny hit the roof of a parked car what, if any, damage would be done to the car's roof?

Answer 1

The Empire State building is 381m tall. If we neglect air resistance (for simplicity) then we can use an equation of motion:

s=ut+½gt^2

u= 0 since it starts from rest so,

t = √2s/g = √(2*381/9.81) = √77.67 = 8.8 seconds

This obviously neglects air resistance. In actual fact it would take longer as the penny would fall with terminal velocity (24 mph if flat up to 74mph if falling on its edge...see here for the calculation http://www.jimcarson.com/2004/01/monday-morning-armchair-physic/)

This was actually investigated by Mythbusters on the Discovery channel. They concluded that the penny's terminal velocity is too low for it to penetrate human skin - let alone penetrate metal, concrete or bone.

http://en.wikipedia.org/wiki/MythBusters_(season_1)#Penny_Drop

Answer 2

The penny would not make it to the ground. It is a common misconception that one can drop a penny from the top of the empire state building and have it reach the ground. It would fall a short distance at which point the wind would just take it away. If we were talking about a created scenario where there is no wind, the penny obviously would reach the ground, but this is to answer the second part of your question. All things in the world will have a terminal velocity, that is to say when an object is falling for a long enough period of time, the object will reach a maximum speed. This speed is determined by the objects weight and the gravity and with the case of the penny it would be tiny and the damage it would create would be just as small. Another fact, A penny's terminal velocity is too low for it to penetrate human skin - let alone penetrate concrete or asphalt - even when fired from a rifle.Therefore, no damage would result. Also I think the myth-busters busted this myth on their show. Check out these links if you think im faking it......




http://en.wikipedia.org/wiki/MythBusters_episodes:_Season_1#Penny_Drop

Answer 3

Chances are it would NOT hit the ground. If you look at the building you can see the the lower floors are wider then the top, so your penny would hit the roof of a lower floor. Even if you threw it hard, the air current would blow it back. The physics answers will talk about maximum velocity etc.

Now driving a golf ball off the top would be way cool. How far would it bounce when it hit?

***UpDate*** Alfred Sauce, you scare me - wow - nice answer

Answer 4

For openers, you'd be arrested for 'reckless endangerment' and probably spend a few months in jail as well as pay a healthy fine.
Terminal velocity for a penny (due to it's fairly large cross-sectional area to mass ratio) is only around 90 mph. But that's plenty fast enough to put a good sized 'dimple' in a car roof or do serious harm to a pedestrian.

Doug

Answer 5

i saw a program in TV about this, a physician said it wont lead to death or a big injury because of the penny's weight ...and he made an experiment .

about how long would it take it to reach the ground, i believe this depends on two things1: its weight 2: the wind , nothing else

if there is no wind it will reach the ground faster ,with wind it will take longer.. maybe a few seconds different

Answer 6

I'm not shore how fast it would fall but once it reaches maximum velocity it can't go no faster, and the maximum velocity of a coin can not damage a car maybe chip the paint a bit, but not course a grate deal of damage

Answer 7

i've seen this question answered. the time can be figured out but i forgot the formula. as for damage, there would be next to none, as damage would be calculated to the coins mass. since the coin would reach terminal velocity with such a small amount of mass, very little damage (maybe a small dent if it was a new crappy car with sheet metal like a soda can) would occur. maybe a paint chip too.

http://en.wikipedia.org/wiki/Terminal_velocity

Answer 8

The Empire State Building is 381 m tall. Therefore, at gravitational acceleration (9.8 m/s^2):

d = 0.5at^2, t = (2d/a)^0.5 = (2 * 381 m/9.8 m/s^2)^0.5 = about 8.8 seconds.

I believe it would cause considerable damage to the car, since it would be traveling at a very high speed. In the absence of air resistance, it would be about (8.8 s)(9.8 m/s^2) = 86 m/s, or about 192 mph. Of course there is air restistance, and a terminal velocity. But its still pretty fast.

Answer 9

if you threw a penny over the empire state building it wouldnt go straight down. its too high up and the wind would pick it up.

Answer 10

omg! watch mythbusters, they did a show on this its soo cool!!