Question

An unwary football player collides with a padded goalpost while running at a velocity of 7.50 m/s and comes to a full stop after compressing the padding and his body 0.350 m. (a) What is his acceleration? (b) How long does the collision last?

a) (a) -375 m/s²; (b) 0.020 s
b) (a) -214 m/s²; (b) 0.035 s
c) (a) -250 m/s²; (b) 0.030 s
d) (a) -150 m/s²; (b) 0.050 s

Answer 1

The football player's acceleration is -375 m/s² and the collision lasts for 0.020 s.

Step-by-step explanation:

To find the acceleration, we can use the equation: final velocity (vf) squared = initial velocity (vi) squared + 2 * acceleration (a) * displacement (d). Here, vf is 0 m/s, vi is 7.50 m/s, and d is -0.350 m (since he comes to a full stop after compressing his body and padding, so the displacement is in the opposite direction of the initial velocity). Plugging in these values, we can solve for a: a = -375 m/s².

To find the time it takes for the collision, we can use the equation: vf = vi + a * t, where vf is 0 m/s, vi is 7.50 m/s, and a is -375 m/s². Plugging in these values, we can solve for t: t = -0.020 s.