Question

A ball is thrown vertically upwards with an initial velocity of $ 20 \, \text{m/s} $. How high will the ball rise? (Take $ g = 10 \, \text{m/s}^2 $)

• A. \( 40 \, \text{m} \)
• B. \(20 \, \text{m} \)
• C. \( 10 \, \text{m} \)
• D. \( 25 \, \text{m} \)

Hint:

Remember: At the highest point, the final velocity of an object thrown vertically upwards is zero. Use this to calculate the maximum height.

Answer 1

The Correct Option is B

Calculate the Maximum Height the Ball Will Rise

We are given the following data:

• Initial velocity \( u = 20 \, \text{m/s} \)
• Acceleration due to gravity \( g = 10 \, \text{m/s}^2 \)

Step 1: Recall the kinematic equation for vertical motion

The equation is: \[ v^2 = u^2 - 2gh \] where \( v \) is the final velocity at the highest point, which is 0 m/s.

Step 2: Substitute the values into the equation

\[ 0^2 = (20)^2 - 2 \times 10 \times h \] \[ 0 = 400 - 20h \] \[ 20h = 400 \] \[ h = \frac{400}{20} = 20 \, \text{m} \]

Conclusion:

The ball will rise to a maximum height of \( 20 \, \text{m} \).

The correct answer is:

Option 2: 20 m