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, assuming negligible air resistance?

a.20 m
b.35 m
c.50 m
d.70 m

Answer 1

The height of the building is approximately 30 meters.

Step-by-step explanation:

To find the height of the building, we can use the equations of motion for vertical motion.

The ball is thrown downward, so the initial velocity is negative (-25 m/s) since the direction is downwards. The time of flight is given as 2.0 s.

Using the equation, h = v0t + (1/2)gt2, where h is the height, v0 is the initial velocity, t is the time, and g is the acceleration due to gravity, we can substitute the known values:

h = (-25 m/s)(2.0 s) + (1/2)(9.8 m/s2)(2.0 s)2

Simplifying this equation gives h = -50 m + 19.6 m = -30.4 m.

Since the height cannot be negative, we take the absolute value and round to the nearest whole number. Therefore, the height of the building is approximately 30 m.