Question

A ball is dropped from a height of 1.30 m. How long does it take to hit the ground? WebAssign will check your answer for the correct number of significant figures. How fast is it going when it hits?

Answer 1

Answer:

a) t= 0.515 s

b) vf= 5.047 m/s

Explanation:

Because ball move with uniformly accelerated movement we apply the following formulas:

d= v₀t+ (1/2)*g*t² Formula (1)

vf= v₀+gt Formula (2)

Where:  

d:displacement in meters (m)  

t : time in seconds (s)

v₀: initial speed in m/s  

vf: final speed in m/s  

g: acceleration due to gravity in m/s²

Known data

v₀=0

d= 1.30 m

g= 9.8 m/s²

Problem development

a) We appy the formula 1 to calculate the time (t):

d= v₀t+ (1/2)*g*t²

1.30= 0+ (1/2)* (9.8)*t²

1.30=4.9*t²

t²=1.30/4.9

$t=\sqrt{\frac{1.3}{4.9} }$

t= 0.515 s

b) We appy the formula 2 to calculate the final speed (vf):

vf= v₀+gt

vf= 0+(9.8)*(0.515)

vf= 5.047 m/s