Homework Help: physics

Posted by Ashley on Saturday, November 17, 2012 at 8:53pm.

A 80kg football player leaps straight up into the air (with no horizontal velocity) to catch a pass. He catches the .43kg ball at the peak of his jump, when he is 17.2 inches off the ground. He hits the ground 1.61 inches away from where he leapt. If the ball was moving horizontally when it was caught how fast was the ball traveling?

physics - Damon, Sunday, November 18, 2012 at 6:02pm
How long does it take to fall 17.2 inches.
(I assume you are working with an ancient text that uses feet and inches so in your world g = 32 ft/s^2)
17.2 inches /12 in/ft = 1.43 ft

d = 1.43 = (1/2) g t^2
1.43 = 16 t^2
t = .299 seconds to fall

So horizontal speed u took us 1.61 inches in .299 seconds
1.61/12 = u (.299)
so u = .449 ft/second

Call ball speed s
total x momentum of system before catch = momentum of ball = .43 s
so
.43 s = u(80.43) = .449 (80.43)
so
s = 84 ft/s
physics - Damon, Sunday, November 18, 2012 at 6:04pm
How long does it take to fall 17.2 inches.
(I assume you are working with an ancient text that uses feet and inches so in your world g = 32 ft/s^2)
17.2 inches /12 in/ft = 1.43 ft

d = 1.43 = (1/2) g t^2
1.43 = 16 t^2
t = .299 seconds to fall

So horizontal speed u took us 1.61 inches in .299 seconds
1.61/12 = u (.299)
so u = .449 ft/second

Call ball speed s
total x momentum of system before catch = momentum of ball = .43 s
so
.43 s = u(80.43) = .449 (80.43)
so
s = 84 ft/s

Answer this Question

Related Questions

Physics - A 70.0 kg football player leaps straight up into the air (with no ...
Physics HW, Help Please - A 70.0 kg football player leaps straight up into the ...
Physics - Tom Brady passes a football – at a velocity of 50 ft/s at an ...
Physics - Football is kicked up into the air with a velocity of 20m/s. a. ...
Physics - Tom Brady (the Patriots’ quarterback) throws a football – at...
Physics - A football player kicks a football with an initial velocity of 30m/s ...
Physics - A football player punts the football so that it will have a hang time ...
MATH - The tail of a giant kangaroo is attached by a giant rubber band to a ...
math - The tail of a giant kangaroo is attached by a giant rubber band to a ...
physical science - a soccer player kicks a ball straight up into the air at 6 m/...

For Further Reading

First Name:
School Subject:
Answer: