Sunday

April 20, 2014

April 20, 2014

Posted by **Anonymous** on Friday, October 5, 2012 at 1:14am.

a) What is the vertical component of the velocity of the ball just after it is released?

b) What is the speed (the magnitude of the velocity) of the ball when it is at the top of its trajectory?

c) What is the speed (the magnitude of the velocity) of the ball just before it is caught?

- Physics -
**Jennifer**, Friday, October 5, 2012 at 9:43amvx(t) = vx0

vy(t) = vy0 - g*t

y = vy0*t - 1/2*g*t^2

x = vx0*t

where y is vertical distance measured from the height of the football player's hand, x is the horizontal distance, t is time, vy0 is the initial speed in the y direction, vx0 is the initial speed in the x direction, and vy(t) is the speed in the y direction as a function of time, and vx(t) is the speed in the x direction as a function of time

When the football player catches the ball at 1.7s, the vertical height y is back at 0, and the horizontal distance is at 30

0 = vy0*1.7 - 1/2*g*1.7^2

30 = vx0*1.7

Solve for vy0 and vx0

a) The vertical component of the velocity of the ball just after it is released is vy(t) evaluated at t = 0

vy(t) = vy0

b) At the top of its trajectory, the ball will be exactly halfway to the receiver, so t = 1.7/2 = 0.85 s. At this time

vy(t) = vy0 - g*0.85

vx(t) = vx0

solve

then the magnitude of the speed is

(vy(t)^2 + vx(t)^2)^0.5

c) Just before the ball is caught, t = 1.7s

vy(t) = vy0 - g*1.7

vx(t) = vx0

solve for vy(t) and vx(t), and then use the formula from part b to calculate the magnitude of the vector

**Related Questions**

math - Please explain in detail so I can understand how to do it: A football ...

Math - We are studying Quadratic formula: A football player punts a ball. The ...

Physics - A football player throws a ball with a horizontal distance of 31.0 m ...

Physics - A football player punts the football so that it will have a hang time ...

physics - A football, if it was kicked when initially at rest, is inflated such ...

physics - A 70.5kg football player is gliding across very smooth ice at 2.05m/s...

physics - A 0.255-kg volleyball approaches a player horizontally with a speed of...

physics - A 0.280-kg volleyball approaches a player horizontally with a speed of...

Physics - Baseball player A bunts the ball by hitting it in such a way that it ...

Physics! - Baseball player A bunts the ball by hitting it in such a way that it ...