Aball is thrown horizontally from the top of a building 0.10 km high. the ball strikes the ground at a point 65 m horizontally away from and below the point of release. what is the speed of the ball just before it strikes the ground?
a) 43 m/s
b) 47 m/s
c) 39 m/s
d) 36 m/s
e) 14 m/s

option B

Explanation:

given,

height of building = 0.1 km

ball strikes horizontally to ground at = 65 m    

speed at which the ball strike = ?

vertical velocity  = 0 m/s

time at which the ball strike

t = 4.53 s

vertical velocity at the time  4.53 s = g × t = 9.8 × 4.53 = 44.39 m/s

horizontal velocity = =14.35 m/s

speed of the ball =

                             = 46.65 m/s

hence, the speed of the ball just before it strike the ground = 47 m/s

The correct answer is option B

the total distance that martina travels that day is

(distance from home to mom's office) plus (distance from mom's office to school)

plus (distance from school to library) plus (distance from library to friend's house)

plus (distance from friend's house to martina's house).

(we don't know what any of these distance actually is.)

it is a negative acceleration