Question

A ball is thrown downward from the top of a building with an initial speed of 25 m/s.

It strikes the ground after 2.0 s. How high is the building?
20 m
30 m
50 m
70 m

Answer 1

h = 69.6 m

Step-by-step explanation:

Data:

• Vo = 25 m/s
• t = 2.0 s
• g = 9.8 m/s²
• h = ?

Formula:

• 
  `\boxed{\bold{h=V_(0)*t+(g*(t)^(2))/(2)}}`

Replace and solve:

• 
  `\boxed{\bold{h=25(m)/(s)*2.0\ s+(9.8(m)/(s^(2))*(2.0\ s)^(2))/(2)}}`

• 
  `\boxed{\bold{h=50(m)/(s^(2))+(9.8(m)/(s^(2))*4\ s^(2))/(2)}}`

• 
  `\boxed{\bold{h=50\ m+(39.2\ m)/(2)}}`

• 
  `\boxed{\bold{h=50\ m+19.6\ m}}`

• 
  `\boxed{\boxed{\bold{h=69.6\ m}}}`

The building has a height of 69.6 meters.

Greetings.