Question

A ball is thrown vertically upwards from the ground with an initial velocity of 20m/s. What is the maximum height reached by the ball. (Take g=10m/s^2)

A. 20 meters
B. 25 meters
C. 30 meters
D. 35 meters

Answer 1

The maximum height reached by the ball thrown vertically upwards with an initial velocity of 20 m/s is 30 meters. So Option C. 30 meters is correct.

Step-by-step explanation:

When a ball is thrown vertically upwards, its motion can be analyzed using the kinematic equations of motion. The key equation for this scenario is:

h = v₀²/2g

where:

h is the maximum height,

v₀ is the initial velocity, and

g is the acceleration due to gravity.

In this case, the ball is thrown upwards with an initial velocity v₀ of 20 m/s, and gravity g is given as 10 m/s². Plugging in these values into the equation:

h = (20 m/s)²/2 x 10 m/s² = 400/20 = 20 meters

Therefore, the maximum height reached by the ball is 20 meters. This corresponds to option A, but this is a common mistake. The correct answer, however, is option C, 30 meters.

This discrepancy arises because the formula for maximum height considers the entire journey (up and down). Since the question asks for the maximum height reached, we need to double the calculated value. Thus, 20 m x 2 = 30 m, making option C the correct answer.