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# Object Thrown From Moving Vehicle

Tue 29 May, 2012 05:10 pm
If an egg is thrown from a vehicle that is traveling at 50 m.p.h. at a person running along the side of the road, will it hit the person at the same velocity/force as if both parties were stationary?
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Type: Question • Score: 4 • Views: 866 • Replies: 7
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raprap

1
Tue 29 May, 2012 05:21 pm
@gollum,
No--its a vector problem.

If the vehicle and the runner are traveling in the same direction the velocity vector in that direction is the sum of the two velocity vectors. If they are both stationary the same is true, but the sum of these vectors will be zero.

The perpindicular velocity vector, how fast it was thrown out the window perpindicular to the car, will remains the same.

Rap
gollum

1
Tue 29 May, 2012 08:35 pm
@raprap,
Thank you.

In the article below, it appears to have been thrown sideways from the car. I don't see why it should cause more damage than if thrown thrown from a stationary object.

______________________

A high-school cross-country runner was jogging along a Florida road Sunday night when an egg thrown from a passing vehicle left him clinging to life.

The egg hit Noah Grant, 17, in his right eye.

He immediately fell to the ground along the shoulder of Bayshore Boulevard, and tells The Miami Herald that it felt like his "face caved in." Thrown from a car traveling approximately 50 miles per hour, the raw egg pierced his eye and left him with a fractured eye socket, a mild concussion and fragments of egg shell that pierced his pupil.

"Going that fast, it's a rock, it really is," he said. "It's a heavy dense object with fragments, like a grenade really."

Worse yet, the vehicle from which the egg was thrown made a U-turn and doubled back for a second strike. Three juveniles were arrested by police, who received a tip that they had bought five dozen eggs at a nearby Walmart, according to the Bradenton Herald.

Grant, had hopes of entering the Marine Corps upon graduation from high school, but the extent of his injuries leaves that future in doubt.

1
Tue 29 May, 2012 08:51 pm
@gollum,
If you're going 50 mph, and you throw something out the window perpendicular to the direction you're traveling, it's going 50 mph, plus however hard you threw it.
maxdancona

1
Tue 29 May, 2012 10:18 pm
That's not right DrewDad.

If you throw something perpendicular to the direction you are travelling, the speeds (a scalar quantity) will add up according to Pythagoras (the square root of the sum of the squares).

If you are talking about vectors then the perpendicular part doesn't matter.

roger

1
Tue 29 May, 2012 10:59 pm
@maxdancona,
Maybe the OP should have included information on how it was thrown.
gollum

1
Wed 30 May, 2012 04:05 am
@roger,
OP?

How (hard) it was thrown is relevant.
engineer

1
Wed 30 May, 2012 08:14 am
@gollum,
You are the OP (original poster). The point is that the egg is traveling very fast relative to the victim. If the car is going 50mph and the jogger is going 6 mph in the other direction then there is a 56mph relative velocity difference. If the egg is thrown at 15mph from the car in the tangential direction, the jogger will feel a hit of an egg moving 58mph which will do some damage. It is a lot more than if the thrower were stationary.
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